Scholarly Literature
This is an aggregation of scholarly literature from peer-reviewed journals, bioRxiv , medRxiv and arXiv preprint servers focused on natural and engineered selfish genetic elements and genetic biocontrol. New citations are added as they appear. This content is intended for anyone interested in the scholarly literature on gene drive and genetic biocontrol.
Insect control by genetic manipulation of natural populations
6300M. J. Whitten, Science, 171:682. 1971-02-19 19:57:36.
The possible use of chromosome rearrangements is considered as a means for introducing genes into insect populations for their own control. The release of laboratory-constructed strains differing from the field population for a number of chromosome interchanges should create an unstable situation leading to the rapid replacement of the field population. This replacement should allow introduction of genes for insecticide susceptibility, cold sensitivity, or the like. The process would produce sterile hybrids while the genetic displacement occurs which itself will contribute to a reduction in pest numbers.
The Sterile-Male Technique Against Tsetse Flies, Glossina Spp
26213D. A. Dame and C. H. Schmidt, 16, 24-30. 1970-03-16 15:05:33.
Simpson (1958) discussed the relationship between the biological characteristics of the genus Glossina and the use of the sterile-male technique in the control of this vector of trypanosomiasis, as did Knipling in an informal report in 1963 on Practical Role of the Sterility Principle for Tsetse Fly Eradication in WHO/Vector Control/27. Knipling estimated that an initial overflooding ratio of sterile to wild males of 3: 1 with successively smaller releases could eradicate a low-density population of flies in 12 months (Table 1) at a cost of about 125/mile2, even if the sterilized males cost as much as 5 cents each. With larger populations, other methods would have to be used to reduce the density before the releases of sterile males. Also, Knipling (1964) emphasized the economic advantage that would be gained by reduction in the total number of sterile males required if their release were preceded by a single application of a nonpersistent insecticide which would eliminate most of the adult population. When populations cover a wide area, simultaneous treatment of the entire infested area might not be feasible. A more realistic approach (Table 2) could be to systemically expand small control areas along a common front (Dame 1968).
Mechanisms of meiotic drive
4502Zimmering, SS, L.; Nicoletti, B., Annual Review of Genetics, 4:409-436. 1970-01-20 00:00:00.
Meiotic drive has been defined by Sandler & Novitski (157) as any alteration of the normal process of meiosis with the consequence that a heterozygote for two genetic alternatives produces an effective gametic pool with an excess of one type; such a pattern of behavior will drastically alter the frequency of alleles in a population in such a way that a driven allele may increase in frequency in spite of deleterious physiological effects. This general concept has, however, been taken to include transmissional anomalies that are not strictly meiotic, but with similar populational consequences [see, for example, Lewontin (93)]; this extended meaning seems justified and thus the more general definition will be used in this review.
Analysis of a general population genetic model of meiotic drive
4501Hartl, DL, Evolution, 24:538-545. 1970-01-19 00:00:00.
The purpose of this article is to present the detailed solution of a model of meiotic drive which Lewontin (1968) has suggested would be helpful in understanding the evo- lutionary dynamics of the t-alleles in the house mouse. Because mice tend to breed in small endogamous family units, however, the deterministic model is only a very rough approximation to what would be expected to occur in nature, and to gain better insight one is forced to undertake Monte Carlo simulation of small populations (Lewontin and Dunn, 1960; Lewontin, 1968).
Meiotic drive in natural populations of Drosophila melanogaster 9: Suppressors of segregation distorter in wild populations
4500Hartl, DL, Canadian Journal of Genetics and Cytology, 12:594-600. 1970-01-18 00:00:00.
A population of Drosophila melanogaster in Madison, Wisconsin, has been screened for suppressors of segregation distorter (SD), an autosomal meiotic drive element found in the same population. Three kinds of suppressors were tested for: (1) Y-linked suppressors, none were found, (2) X-linked suppressors, whose frequency was found to be 85%, and (3) autosomal dominant suppressors, which occur in 45% of autosome complements.The frequency of X-linked suppressors is comparable to that found in a Japanese population; autosomal suppressors are much more frequent in Madison than in Japan (Katoaka, 1967). The similarity in the frequency of sex-linked suppressors may result from the meiotic drive shown by the suppressor-X itself; the difference in the frequency of autosomal dominant suppressors is possibly related to a higher frequency of SD itself in the Madison population.
Possible use of translocations to fix desirable genes in insect populations.
4503Curtis, CF, Nature, 218:368-369. 1968-01-21 00:00:00.
Chromosome translocation heterozygotes (T/+) are usually semisterile, but translocation homozygotes (T/T) if viable are usually fully fertile. If such a viable translocation were produced in an insect pest, T/T insects could be reared in captivity and released into the wild, where matings with wild types (+/+) would produce T/+ progeny.
Meiotic drive and visible polarity in Drosophila spermatocytes
4504Yanders, AFB, J. G.; Peacock, W. J.; Goodchild, D. J., Genetics, 59:245-253. 1968-01-02 00:00:00.
The model for meiotic drive presented by PEACOCK and ERICKSON (1965) demands that an intracellular differentiation exists at the time of the first meiotic division in spermatocytes. As a result of this differentiation, one of the spindle poles at anaphase I will lead to the formation of two functional sperm, while the other pole will yield two nonfunctional sperm. This model can be used to explain cases of meiotic drive, such as Segregation-Distorter (SD) ( SANDLER, HIRAIZUMI, and SANDLER 1959), if one member of a chromosome pair moves to the functional pole in a nonrandom fashion, and is thereby preferentially included in the functional gametes.
Eradication of Culex pipiens fatigans through cytoplasmic incompatibility.
6278H. Laven, Nature, 216:383. 1967-10-28 16:57:49.
Culex pipiens fatigans is the chief vector of filariasis in south-east Asia. Urbanization has often caused the numbers of this mosquito-and with it the danger of filariasis infection-to increase alarmingly. The natural vigour, tolerance and fast development of resistance to insecticides of this mosquito necessitate the development of other control methods, and cytoplasmic incompatibility2 seems to be an ideal means.
Extraordinary sex ratios
6186W. D. Hamilton, Science, 156:477-488. 1967-04-03 19:10:19.
The two sexes are usually produced in approximately equal numbers. Fisher (1) was the first to explain why, under natural selection, this should be so, irrespective of the particular mechanism of sex determination. His rather tersely expressed argument has been clarified by subsequent writers (2) and seems to be widely accepted. In bare outline, the factor of parental care being ignored, it may be given as follows: 1) Suppose male births are less common than female. 2) A newborn male then has better mating prospects than a newborn female, and therefore can expect to have more offspring. 3) Therefore parents genetically disposed to produce males tend to have more than average numbers of grandchildren born to them. 4) Therefore the genes for male-producing tendencies spread, and male births become commoner. 5) As the 1:1 sex ratio is approached, the advantage associated with producing males dies away. 6) The same reasoning holds if females are substituted for males throughout. Therefore 1:1 is the equilibrium ratio.
Genetic distortion of sex ratio in a mosquito Aedes aegypti
4505Hickey, WAC, G. B., Genetics, 53:1177-1196. 1966-01-03 00:00:00.
CRAIG, HICKEY and VANDEHEY (1960) reported that a hereditary factor transmitted by males was responsible for high male ratios in A. aegypti. This phenomenon was designated as male-producing or MP. Males from high maleproducing families produced a high proportion of males in their own progeny, regardless of the type of female to which they were crossed. This condition was not due to selective mortality, at least in postgametic stages. In 1960, nothing was known about the sex-determining mechanism in A. aegypti. In addition, the male-producing lines available for study were highly variable in expression. These factors hampered more precise analysis of the mechanism of inheritance of MP. The present work was initiated because new crosses with different strains gave more pronounced and predictable distortion of sex ratios. Earlier strains gave about 15 to 30% female, whereas present lines produce about 0 to 15% female. This paper presents an analysis of the mode of inheritance of MP. In addition, data suggesting the mechanism of action are included. Separate reports will be published elsewhere on ( 1 ) the distribution and behavior of MP in experimental populations and (2) the effect of environment on expression of MP. A more detailed account of some of this work is given by HICKEY (1965a, b). Nomenclature used ih these preliminary reports is superseded by that in the present work.
Meiotic drive in Drosophila involving chromosome breakage
4506Erickson, J, Genetics, 51:555-571. 1965-01-04 00:00:00.
In ordinary genetic systems the members of a pair of unlike alleles, or of a pair of unlike chromosomes, are recovered in equal numbers among the off spring, barring complications affecting viability. Contrary to this expectation, in a number of studies it has been found that one allele or chromosome is recovered in significantly more than 50 percent of the functional gametes. The time and mode of the action resulting in inequality varies; where these phenomena result from events of the meiotic process they are known as instances of meiotic drive (SANDLER and NOVITSKI 1957). The case described herein was isolated from a chronically irradiated population (NOVITSKI and HANKS 1961), and was referred to as “29G” previously (HANKS 1961; ERICKSON and HANKS 1961). HANKS (1964) has renamed the line “RD”, referring to a disruption in recovery of the Y chromosome. which gives rise to a high-female sex ratio in the off spring of RD males.
Aanalysis of case of meiotic drive in Drosophila melanogaster
4507Hanks, GD, Genetics, 50:123-130. 1964-01-05 00:00:00.
IN the past ten years there has been a renewed interest in the abnormal recovery of chromosomes after meiosis; see for example DUNN (1953); NOVITSKI and SANDLER (1957) ; SANDLER and NOVITSKI ( 1957) ; LINDSLEY and SANDLER (1958); NOVITSKI and HANKS (1961); and MAGUIRE (1963). When the two types of gametes from a heterozygote are recovered with unequal frequency because of a meiotic mechanism the force resulting is called meiotic drive (SANDLER and NOVITSKI 1957). Such a force is capable of altering allele frequencies in a population, and thus the evolutionary consequences are potentially important; this has been discussed in detail by DUNN (1953) and SANDLER and NOVITSKI (1957). The case analyzed here was found by testing chromosomes from population cages maintained by WALLACE atCold Spring Harbor which were subjected to low intensity radiation for over 200 generations (WALLACE 1956). Earlier studies have indicated that the case here analyzed does not produce its effect by zygotic mortality, is manifested only in the male, and is greatly altered by temperature changes during the period of meiosis in the male (NOVITSKI and HANKS 1961; ERICKSON and HANKS 1961). This paper presents the genetic analysis of this case showing the extent to which its effect may be modified by substituting different sex chromosomes and autosomes.
Applications of genetic technology to mosquito rearing
6098G. B. Craig, Bulletin of the World Health Organization, 29:89-97. 1963-01-02 16:40:36.
Since the development of insecticide-resistance and the consequent partial failure of the chemical approach to the control of disease vectors, interest in the biological approach has re-awakened. An aspect of the latter approach that is of great current interest is " autocidal control "-that is, the use of insects for their own destruction. This paper discusses the various ways in which genetic mechanisms can be used to bring about the destruction of harmful insects, with special reference to those of medical importance. The author considers that the prospects for the genetic control of vector species are good, but stresses that before genetic methods can be applied on a field scale certain requirements must be met. For example, genetic technology must be expanded, a firm background of genetic knowledge of vector species must be built up, a great deal more information about vector ecology, particularly population dynamics, must be acquired, and techniques for the mass production of vector insects under controlled conditions must be developed.
On the role of lethal mutants in the control of populations
6101R. C. Von Borstel and A. A. Buzzati-Traverso, Radioisotopes and Radiation in Entomology: Proceedings of a Symposium, Bombay, 5-9 December, 1960, 1962:273-278. 1962-01-02 16:52:59.
On the role of lethal. mutants in the control of populations. Population control by release of irradiated males requires that the sperm must be damaged by radiation. The type of damage induced by radiation imposes a restriction on which species may be controlled because if the sperm are functionally damaged by radiation, then for effective control, the females must be monogamous. If dominant lethality is induced in sperm then either polygamy or monogamy may prevail. It is generally accepted that dominant lethal events are induced in sperm at doses much lower than those required to hamper sperm function or cause sperm inactivation. With Drosophila it is possible to test directly the effect of releasing irradiated males into an artificial population where polygamy is the rule. Preliminary experiments have been performed under conditions of unlimited production of offspring. It appears that radiation induces dominant lethality in sperm, and the sperm that bear dominant lethals are able to compete successfully with normal sperm. A series of tests are currently under way to ascertain the degree of induced dominant lethality and sperm inactivation at different X-ray dosages. A series of experiments are outlined in a general discussion of the possible use of dominant and recessive lethals for bringing about collapse of artificial and natural populations.
Meiotic drive in natural populations of Drosophila melanogaster .7. Conditional segregation distortion – a possible nonallelic conversion
4512Sandler, LH, Y., Genetics, 46:585-604. 1961-01-10 00:00:00.
Males, heterozygous for the Segregation-distorter (SD) allele (located in or near the centromeric heterochromatin of the right arm of chromosome 11) and a standard tester second chromosome, regularly produce a preponderance of functional SD-bearing sperm ( SANDLER, HIRAIZUMI and SANDLER 1959). Segregation in heterozygous SD females, on the other hand, is always normal. It has been found, however, that, for certain SD lines, if the SD-bearing chromosome is inherited from the female parent, then, in a fraction of F, male sibships, only one half of the heterozygous SD sons exhibit the phenomenon of segregationdistortion; in the other half of the sons, segregation is normal. In the following generation, all of the males exhibit abnormal ratios irrespective of whether or not their father showed an abnormal ratio. Those females that produce sons. only one half of which distort, are referred to as conditioned; the phenomenon is termed conditional distortion ( SANDLER and HIRAIZUMI 1959)
Meiotic drive in natural populations of Drosophila melanogaster .8. A heritable aging effect on phenomenon of segregation distortion
4511Sandler, LH, Y., Canadian Journal of Genetics and Cytology, 3:34-46. 1961-01-09 00:00:00.
Second chromosomes have been found in natural populations of Drosophila melanogaster that contain an abnormal centromere region which conditions a highly aberrant segregation ratio in heterozygous males (Sandler, Hiraizumi, and Sandler, 1959). In particular, when a chromosome carrying this abnormal region (symbolized SD for Segregation-distorter) is made heterozygous with a normal second chronlosome (routinely a standard tester chromosome marked by the recessives cn and bw) in males, and backcrossed to homozygous cn bw females, 90 per cent or more of the F1 receive the SD-bearing second chromosome. These abnormal segregation ratios are not accompanied by egg mortality. It has now, been found that as heterozygous SD males are aged, the segregation ratios become less abnormal. When, moreover, young sons of aged fathers are examined, it is found that they too exhibit less extreme segregation ratios. Indeed, changes in the segregation ratio induced by aging may persist in selected, males for at least five generations and possibly indefinitely. The evidence demonstrating a heritable aging effect and a consideration of certain other questions relevant to the aging phenomenon are presented below.
Analysis of irradiated Drosophila populations for meiotic drive
4510Novitski, EH, G. D., Nature, 190:989-990. 1961-01-08 00:00:00.
The existence of chromosomes or alleles that are represented in the gametes of a heterozygote with a frequency greater than the expected 50 percent is now well established for a variety of species. The immediate population result of introducing such a chromosome or allele must be a sharp increase in its frequency, alon with any other genes associated by linkage, independent of or, indeed, in spite of, their phenotypic effects. For this reason such phenomena have been referred to as cases of 'drive' and, more specifically, as 'meiotic drive' when the basis is found in some aberration of meiosis. Such instances would seem to provide an unparalleled opportunity for the study of population dynamics, for example, the efficacy of response of natural selection to unfavourable genes. It seemed worth while, therefore, to determine whether such chromosomes or alleles characterized by drive might be induced in the laboratory.
Meiotic drive in natural populations of Drosophila melanogaster .6: A preliminary report on presence of segregation-distortion in a Baja california population
4509Mange, EJ, American Naturalist, 95:87-96. 1961-01-07 00:00:00.
Meiotic drive is a term coined by Sandler and Novitski (1957) to describe; the situation whereby a heterozygote produces gametes containing an excess; of one allele, rather than the expected equality. As a consequence of such; aberrant segregations, gene frequencies within a population may be radically; altered; indeed, detrimental or lethal genes closely linked to the driven gene; may increase in frequency, thereby leading to a reduction in fitness or pos; sibly even to extinction of the population.; An instance of meiotic drive in Drosophila melanogaster, discovered by; Hiraizumi in a Madison, Wisconsin, population, has been reported by Sandler,; Hiraizumi and Sandler (1959). The phenomenon, termed segregation-distortion,; was found to depend upon a locus designated SD, which is located in the; centromeric heterochromatin of chromosome II. The phenomenon is ex; pressed in males only.; Since segregation-distortion was originally found in a natural population,; the question arose as to whether the phenomenon is of recent origin and; therefore localized in the vicinity of Madison, or well established and hence; widespread among natural populations of Drosophila melanogaster. There; fore, the screening of wild populations for SD (or for any other type of aber; rant segregation) was undertaken. In small samples from only thirteen popu; lations, SD has been detected in one Baja California population as well as; in three other rather widely separated Madison populations. This report will; be confined to establishing that the locus discovered in the southern Cape; region of Baja California (specifically, from Rancho La Burrera near the; west base of Sierra de La Laguna, and a Pleistocene lake relic, called; La Laguna, in the same range) is indeed SD.
Time of temperature sensitivity of meiotic drive in Drosophila melanogaster
4508Erickson, JH, G. D., American Naturalist, 95:247-250. 1961-01-06 00:00:00.
In a line of Drosophila melanogaster demonstrating meiotic drive, it was found that the high recovery rate of the X-chromosome could be nearly nullified by temperature treatment. A series of experiments were carried out to determine at what stage of the life-cycle this treatment is effective. The effect is observed to occur during a part of the process of spermatogenesis, either during the primary spermatocyte stage or extending through this and the meiotic divisions which follow.
Inherited male-producing factor in Aedes aegypti
6096G. B. Craig, W. A. Hickey and R. C. Vandehey, Science, 132:1887-1889. 1960-12-23 14:59:02.
An inherited factor causes a predominance of males in certain strains and in progeny of single pairs of Aedes aegypti L. This factor appears to be transmitted only by males and is not due to differential mortality, at least in postgametic stages. Mass release of male-producing males might be used in control operations.
Meiotic drive in natural populations of Drosophila melanogaster .4: Instability at the Segregation Distorter locus
4515Sandler, LH, Y., Genetics, 45:1269-1287. 1960-01-13 00:00:00.
In a collection of flies from a natural population of Drosophila melanogaster, several second chromosomes have been isolated that contain, in the centromere region .of chromosome 11, a locus (named segregation-distorter and symbolized SO) that conditions, in heterozygous males, a highly abnormal segregation ratio in favor of the SD-bearing chromosome. Experiments bearing on the cytogenetic basis of the phenomenon of segregation-distortion and on the formal genetics of the SD locus have been reported by SANDLER, HIRAIZUMI, and SANDLER (1959). and by SANDLER and HIRAIZUMI ( 1959).
Meiotic drive in natural populations of Drosophila melanogaster .5. On the nature of the SD region
4514Sandler, LH, Y., Genetics, 45:1671-1689. 1960-01-12 00:00:00.
Second chromosomes were collected from nature which, when heterozygous with a normal chromosome 1 in males, are present in functional sperm much more often than the expected 50 percent. This phenomenon, named segregation distortion, was found to depend on a locus named Segregation-distorter (symbolized SD), which is located near the centromere (and probably in the right arm) of chromosome 1
Meiotic drive in natural-populations of Drosophila melanogaster 3: Populational implications of the Segregation-Distorter locus
4513Hiraizumi, YS, L.; Crow, J. E., Evolution, 14:433-444. 1960-01-11 00:00:00.
If, among the successful gametes frm heterozygotes, one allele is regularly included in more than half, it may increase in frequency even if it has a harmful effect. Unequal gamete production, when attributable to the mechanics of meiosis, has been called meiotic drive (Sandler and Novitski, 1957). An example is segregation-distortion in Drosophila melanogaster, the cytogenetic behavior of which has been reported by Sander, Hiraizumi and Sandler (1959) and Sandler and Hiraizumi (1959)
Meiotic drive in natural populations of Drosophila melanogaster .1. The cytogenetic basis of segregation distortion
4517Sandler, LH, Y.; Sandler, I., Genetics, 44:233-250. 1959-01-15 00:00:00.
Meiotic drive has been defined as a force, potentially capable of altering gene frequencies in natural populations, which somehow depends upon the nature of the meiotic divisions; specifically, when the meiotic divisions are such that the two kinds of gametes from a heterozygote are produced in a ratio different from 1 : 1 ( SANDLER and NOVITSKI 195 7). There have been reported numerous cases which either are, or may be, examples of meiotic drive. These include cases in Drosophila ( GERSHENSON 1928; STURTEVANT and DOBZHANSKY 1936; NOVITSKI 1951 ; NOVITSKI and IRIS SANDLER 1957; LINDSLEY and SANDLER 1958), in maize (RHOADES 1942; LONGLEY 1945), in tobacco (CAMERON and MOAV 1957), and possibly in mice (DUNN 1953) and in man (DUNN 1953; SANDLER and NOVITSKI 1957). The purpose of this paper is to present a first account of the results of a series of studies designed to elucidate the cytogenetic basis of a case of meiotic drive which was discovered in a natural population of D. melanogaster. In this population there has been found a second chromosome locus, located in or near the proximal heterochromatin and called segregation-distorter (symbol, SO), which is recovered much more frequently than its normal allele among the progeny of heterozygous male parents. This phenomenon, to which the name segregation distortion has been applied, (1) has never been found to occur in females, (2) apparently requires synapsis (particularly in the region of the locus in question) in order to operate, and (3) comes about as a result of the failure of sperm carrying the normal allele to be formed or to function normally. The evidence bearing on these, and certain other points, and a cytogenetic model to account for the results are presented below.
Meiotic drive in natural populations of Drosophila melanogaster 2. Genetic variation at the Segregation Distorter locus
4516Sandler, LH, Y., Proceedings of the National Academy of Sciences of the United States of America, 45:1412-1422. 1959-01-14 00:00:00.
It has now been found that the proportion of heterozygous SD males resulting from any given cross which exhibits segregation-distortion, and the amount of distortion that any particular male shows (the k value), varies widely depending upon the precise source and history of the SD-bearing and the SD+-bearing chromosomes in the heterozygotes being tested. It is the purpose of this report to present a general account of the kinds of variations in the behavior of SD which have been observed. More fully documented reports of each phase of the work are currently in preparation, and will be presented elsewhere. For this reason, extended discussion of these variations and comparable systems in other organisms has been omitted.
Possible replacement of malaria mosquitoes
6118S. Avery Jones, Transactions of The Royal Society of Tropical Medicine and Hygiene, 51:469-470. 1957-08-10 19:43:41.
Sir,--The purpose of this letter is to draw the attention of research workers in control of mosquito colonies to the possible value of investigating the factors governing the infection of mosquitoes with parasites of human malaria. If a strain of a vector species could be isolated that has inability to become infective as a dominant characteristic, the way would be opened up to implant such mosquitoes in areas where the normal vectors of the same species have been reduced in numbers. There is the hope that they would breed and become locally predominant.
Meiotic drive as an evolutionary force
4518Sandler, L. and Novitski, E., American Naturalist, 91:105-110. 1957-01-16 00:00:00.
A heterozygote for alleles A and A' ordinarilly produces gametes carrying each of the alleles with a frequency of 50 per cent. The constancy of allele frequencies from one generation to the nest in natural populations of diploid species depends on this equality, which itself depends on the nature of the meiotic divisions. As the study of the genetics of higher organisms becomes more precise and extensive, an increasing number of cases is found in which heterozygotes of certain constitutions fail to produce the two kinds of gametes with equal frequency. Such a pattern of behavior will drastically alter frequencies of alleles in a population; where such a fouce, potentially capable of altering gene frequencies, is a consequence of the mechanics of the meiotic divisions, we suggest that the name meiotic drive be applied. The distinction between meiotic drive and the superficially similar phenomenon of gametic selection and gametic competition may be operationally difficult in those instances in which a detailed cytogenetic study cannot be made. The later, however, represent selecdtion in the ordinary sense, operating in the haploid phase, and as such their effectiveness is directly dependent on the gene content (fitness) of the gametes, whereas the effectiveness of the former is independent of the gene content in the ordinary sense.
Inheritance in Nicotiana tabacum XXVII. Pollen Killer, An alien genetic locus inducing abortion of microspores not carrying it
6116D. R. Cameron and R. M. Moav, Genetics, 42:326. 1957-01-02 19:37:02.
A cytogenetic study of experimental introgression from N. plumbaginifolia (pbg) into N. tabacum (tbc) has been pursued in this laboratory for several years (CLAUSEN 1952). In the hybrid derivatives it was observed that genically controlled pollen abortion was associated with the addition of a pbg chromosome to the tbc complement. This chromosome also carried the locus (Bs) determining resistance or probably immunity to black shank, a serious disease of commercial tobacco caused by Phytophthora parasitica var. nicotianae. (For description see CLAYTON and AICAIVRTRY 1950). Paradoxically, it developed that the pbg chromosome under study produced its effect on gametophytes in which it was not present. Thus, the male gametophytes containing a complete set of 24 tbc chromosomes degenerate while most of the functional pollen had the constitution 24 tbc + 1 pbg. This paper presents a description of the genetic aspects of the problem with some suggestions as to the possible method of action of the locus involved. Certain other phases of the larger investigation will be mentioned but only as they apply to the pollen lethal condition. The investigation was initiated by the late PROF. R. E. CLAUSEN who participated actively in the work presented here.
Studies of the genetic variability in populations of wild house mice .2. Analysis of eight additional alleles at locus – T
6113L. C. Dunn, Genetics, 42:299-311. 1957-01-02 19:27:44.
1 Eight additional lethal alleles at locus T are described, each derived from a wild heterozygote in one of six different wild populations. 2. The frequency of heterozygotes appears to be high in most wild populations, possibly as high as 50 percent. 3. In two of the populations in which several heterozygotes were found, the same allele was isolated from each heterozygote of the same population. One heterozygote was found in each of two subpopulations on the same farm. These two alleles have not been shown to be different. One wild heterozygote from another population transmitted two different alleles; probably one was a new mutant, giving rise to the possibility that more than one allele may occur in the same population, although the rule at present is to find but one type of variant allele per population. 4. All wild t alleles show the “male segregation ratio peculiarity” by which male heterozygotes transmit the t allele to a great majority (about 96 percent) of the offspring. This may be due to the effects of natural selection on factors favoring high transmission ratios. 5. t alleles from the wild fall into at least three groups, one with three viable alleles, and two groups of lethals. Lethals within the same group have not formed viable compounds when combined; lethals belonging to different groups do form viable compounds by complementary interaction and are thus shown to be nonidentical. 6. Since 29 alleles have now been detected at this locus, many of which are nonidentical, the locus is assumed to contain many sites of mutation and to have great potential complexity.
Screw-worm control through release of sterilized flies
6107A. H. Baumhover, A. J. Graham, B. A. Bitter, D. E. Hopkins, W. D. New, F. H. Dudley and R. C. Bushland, Journal of Economic Entomology, 48:462-466. 1955-08-03 17:00:44.
Screw-worms, Callitroga hominivorax (Cqrl.), did not exist in the southeastern United States until about 20 years ago, and it is probable that, if the present infestation could be eradicated, the area might be kept free of infestation through inspection of livestock shipments originating in infested areas
Possibilities of Insect Control or Eradication Through the Use of Sexually Sterile Males
6006E. F. Knipling, Journal of Economic Entomology, 48:459-462. 1955-08-01 19:58:21.
The purpose of this paper is to consider the possibility of controlling insects by releasing sexually sterile males among the existing natural population. The principles involved will be described and the potentialities as well as the limitations of the method as we know them at present, will be discussed.
Eradication of screw-worms through release of sterilized males
6091R. C. Bushland, A. W. Lindquist and E. F. Knipling, Science, 122:287-288. 1955-01-02 14:50:36.
Although the sterilizing effect of ionizing radiations has been known for years, it is only recently that entomologists have attempted to take advantage of the phenomenon for insect control. Knipling (1) has theorized on the effects of releasing sterilized males among a normal insect population. In 1947, on a visit to the Kerrville, Tex., laboratory, he proposed investigations on the mating habits of the screw-worm, Callitroga hominivorax (Cqrl.), and experiments with sterilized males. In such experiments Bushland and Hopkins (2) found that screw-worms were easily sterilized by exposing pupae to x-rays or gamma rays. They showed that under laboratory conditions male screw-worms mated repeatedly but fe males only once. If a female mated with a sterilized male it did not mate again and laid eggs that did not hatch. When mixed populations of normal and sterilized insects were observed in cages, the sterilized and normal males competed about equally for mates.
Mutable loci in maize.
6388B. McClintock, Carnegie Inst. Washington Year Book, 47:155-169. 1948-02-10 16:25:33.
Previous reports have state that the number of unstable loci have recently arisen in maize culture. In a particular cell of a plant, a normal "wild-type" locus becomes altered; the normal, dominant expression of this locus changes and gives rise to a recessive expression (or, in several cases, a recessive locus become unstable and mutates toward a dominant expression). This expression of the locus need not be permanent. In some decendent cells, a second change may occur within the locus that results in the restoring of the capacity of thelocus to express the dominant phenotype or brings about an intermediate expression between full recessive and full dominant. In the latter case, a third alteration may occur in some decendent cells that steps up the phenotype expression toward the full dominant or reduces it toward the full recessive.
Experiments in the hybridisation of tsetse-flies (Glossina, Diptera) and the possibility of a new method of control.
6139F. L. Vanderplank, Transactions of the Royal Entomological Society of London, 98:1-18. 1947-01-02 21:38:18.
Hybridisation of Glossina morsitans Westwood, G. swynnertoni Austen and G. pallidipes Austen was attempted in order to discover(a) Whether the three could be regarded as distinct species or as sub-species of morsitans ; (b) Whether they would mate freely with one another, and if not by what means the three closely allied forms distinguished their own kind ; (c) Whether morsitans and swynnertoni would readily produce hybrid offspring, and if so, what proportion of females would do so, and what proportion of hybrids would be sterile ; (d) Finally, whether interference with one species by another could be used as a measure of control. I also wanted to explore other details including markings, colouration and nature of the genitalia of the hybrids, and whether these characters were constant or variable.
Parasitic nature of extra fragment chromosomes
6003Östergren G., Botaniska Notiser, 2:157-163. 1945-12-30 19:52:12.
This paper is intended as a contribution to the discussion concerning the significance of the extra fragments or »accessory chromosomes» as they are called by Håk ansso n(1945), which are not too rarely found in cross-fertilizing populations. I think reasonable support may he given to the view that in many cases these chromosomes have no useful function at all to the species carrying them, but that they often lead an exclusively parasitic existence.
Tsetse hybrids
6145W. H. Potts, Nature, 154:606-607. 1944-11-11 21:48:03.
IN 1936 I attempted to cross various species of tsetse (Glossina) with the idea that, should they hybridize readily, and should the resultant hybrids prove sterile, this might be tried as a measure of control. Corson had already, in 1932, obtained three offspring from crosses between male G. swynnertoni and female G. morsitans; he suggested, however, that these might not be true hybrids, but the result of parthenogenesis (see further details in the accompanying communication by Mr. F. L. Vanderplank). I obtained a number of offspring from this and other crosses, but as a slight doubt arose as to whether they were authentic hybrids, the results were never published.
Hybridization between Glossina Species and Suggested New Method for Control of Certain Species of Tsetse
6142F. L. Vanderplank, Nature, 154:607-608. 1944-11-11 21:43:25.
Corson and Potts record crossing Glossina swynnertoni Aust. with G. morsitans Westwood. Corson crossed twelve female G. morsitans with male G. swynnertoni, of which only two females produced a total of three pupæ. All his females lived long enough for reproduction to take place. He records the offspring, all females, as being identical with pure-bred G. morsitans, and suggested parthenogenesis. Potts crossed both male G. morsitans with female G. swynnertoni and male G. swynnertoni with female G. morsitans (see accompanying communication by Mr. W. H. Potts).
Preferential segregation in maize
6000M. M. Rhoades, Genetics, 27:395-407. 1942-12-30 19:47:18.
An abnormal type of chromosome 10, found by Longley in maize from the s.-w. part of the U. S., is preferentially segregated during megasporogenesis. More than 70% of the ovules receive the abnormal chromosome instead of the 50% expected with random segregation. At pachytene the length of the extra piece of chromatin in the abnormal chromosome is slightly greater than the short arm of chromosome 10. The proximal and distal portions of the extra piece are euchromatic, but a large and conspicuous knob lies between the 2 euchromatic portions. The origin of this extra piece is unknown. Pollen with the abnormal chromosome 10 is only partially successful in competing with pollen possessing a normal chromosome 10. Extra chromatin present in the abnormal chromosome may impair pollen-tube growth. The excess of ovules with the abnormal type of chromosome is due neither to abortion of ovules with a normal chromosome nor to megaspore competition. The R locus, known to lie in the long arm of chromosome 10, proved to be closely linked to the extra piece of chromatin which is believed to be inserted near the tip of the long arm. The observed % of recombination (1-2%) is probably less than the amt. occurring distal to R in stocks carrying 2 normal chromosomes 10. Crossing-over in the gR region is not affected when the abnormal chromosome is heterozygous, and crossing-over in this interval did not affect preferential segregation. Evidence was obtained indicating the influence of the environment on the degree of preferential segregation.
On the possibility of a new method for the control of insect pests.
6157A. S. Serebrovskii, Zoologicheskiĭ zhurnal, 19:618-630 (in Russian). 1940-01-03 16:43:28.
ON THE POSSIBILITY OF A NEW METHOD FOR THE CONTROL OF INSECT PESTS. The new principle of insect control consists in disturbing the propagation of the pest population by means of translocations. It is well known that individuals heterozygous for some translocations usually form a portion of aneuploid gametes and give a more or less inviable aneuploid progeny. On releasing, therefore, a sufficient number of individuals with a chromosome set altered by. translocations into a wild population (with allogamous propagation), there will arise heterozygotes for translocations yielding a certain percentage of inviable offspring. Crosses inside this population will be similar to those between species with resulting sterility of hybrids. The theoretical analysis reveals that if a wild population is mixed in proportion 1:1 with some race containing only one translocation viable in homozygous condition and giving in heterozygotes 50% of aneuploid gametes, the reproduction of the population will be reduced by 43%. If several races with different allelic translocations are released the reduction of reproduction in the population can reach 75%, and if races with 4-5 independent translocations are used the reduction can attain 95%-99% and even more. A population consisting of races with different translocations cannot remain in balance. Those types of chromosomes which happened to be in minority are subjected to elimination. Yet this process of elimination will go on during many generations and thus the disturbance of reproduction will be protracted. By an additional releasing of eliminating race, this disturbance can be maintained permanently. Diverse variants of this method are possible, depending upon the biology and economic importance of injurious insects, the cost of breeding translocated races in laboratories, the difficulties of obtaining viable translocations, etc. It is possible, for instance, to release only males, a method in which there is evidently no danger at all. The present investigation is a purely theoretical one. For the purpose of verifying experimentally this idea work has been started with Musca domestica and Calandra granaria - two insects widely differing in their cytogenetics, ecology and the kind of damage caused.
A new sex-ratio abnormality in Drosophila obscura
6047S. Gershenson, Genetics, 13:488. 1928-12-30 21:32:10.
1. The sex-ratio in the normal lines of Drosophila obscura is very near to the theoretical 1 : 1. 2. Out of 19 females caught in nature, two were heterozygous for a gene which causes strong deviations in the normal sex distribution. 3. The researches made have shown that this gene is localized in the X-chromosome and is transmitted like an ordinary sex-linked gene. 4. This gene is absolutely sex-limited, as it is not manifested either in heterozygous or homozygous females. 5. The males bearing this gene give in their progeny about 96 percent of females and only about 4 percent of males. 6. This gene has no influence on the development of the zygotes already formed, but acts directly upon the mechanism of sex-distribution. It provokes a sharp preponderance of females by almost totally removing the spermatozoa with the Y-chromosome from the fertilization process, acting thus like a gametic lethal (in the genetic sense of this term).
Sur la reproduction des souris anoures
6057N. Dobrovolskaia-Zavadskaia and N. Kobozieff, Comptes rendus des séances de la Société de biologie et de ses filiales, 97:116-119. 1927-06-15 15:44:03.
Nous ne connaissons que deux lignees de Souris sans queue, celle de Lang (1913), et cell de Duboscq (1922). L’elevange de Lang (lignee des Souris brachyures et anoures du preparateur Alfred Nageli) a donne 199 Souris normales, pour 173 brachyures et 9 anoures. Croisses entre ells et aveec des bachyures, les Souris anoures n’ont donne aucune reproduction. Dans la lignee du P Duboscq, provenant d’une femelle anoure A et de son frere normal, et comportant 25 petis en 8 portees, il y avait 8 anoures, don’t la plupart moururent jeunes.
