Scholarly Literature

This is a database of scholarly literature that concentrates currently on natural and engineered selfish genetic elements (gene drives).  The latest are shown here.
Disclaimer>

Male biased sex ratio in the Mediterranean fruit fly Ceratitis capitata, an example of Y-chromosome meiotic drive

4268
Shahjahan, RMR, P. A.; Cook, L. M.; Wood, R. J.,  Heredity,  96:464-470. 2006-01-06 00:00:00.
A case of Y-chromosome meiotic drive is reported in the Mediterranean fruit fly Ceratitis capitata. It arose in an irradiated male and results in excess of males. Male excess is inherited strictly from father to son. A Y-linked factor MP (male producer) is proposed. Higher drive can be selected, but distortion declines rapidly in the absence of selection. Hybrid males from crosses between driving males and nondriving females also show drive but to a reduced extent, suggesting the action of suppressors. Sex ratio distortion is independent of postzygotic mortality, and is not associated with an obvious chromosome arrangement. Spermiogenesis in driving males is characterised by abnormalities in sperm tails and reduced numbers in some sperm cysts, whereas neighbouring cysts of the same MP testis are essentially wild type. The average number of missing sperms plus deformed sperms approximates to the average depression in female recovery among the progenies of siblings, suggesting that most of the missing or abnormal sperms would have given rise to females, that is, they would have been X-bearing. To explain the heterogeneity between neighbouring cysts, a theory is proposed that links it to variation in X-chromosome sensitivity to MP, arising by random suppression of the genetic basis of sensitivity during the six mitotic divisions in the origin of the cyst from its stem cell before meiosis.

The maize Ab 10 meiotic drive system maps to supernumerary sequences in a large complex haplotype

4267
Mroczek, RJM, J. R.; Luce, A. C.; Hiatt, E. N.; Dawe, R. K.,  Genetics,  174:145-154. 2006-01-05 00:00:00.
The meiotic drive system on maize abnormal chromosome 10 (Ab10) is contained within a terminal domain of chromatin that extends the long arm of Ab10 to similar to 1.3 times the size of normal chromosome 10L. Ab10 type I (Ab10-I) does not recombine with normal chromosome 10 (N10) over an similar to 32-cM terminal region of the long arm. Comparative RFLP mapping demonstrates that multiple independent rearrangements are responsible for the current organization of Ab10-I, including a set of nested inversions and at least one long supernumerary segment at the end of the chromosome. Four major meiotic drive functions, i.e., the recombination effect, smd3, 180-bp neocentromere activity, and the distal tip function, all map to the distal supernumerary segment. TR-1-mediated neocentromere activity (the fifth known drive function) is nonessential in the type II variant of Ab10 and maps to a central region that may include a second supernumerary insertion. Both neocentromere activity and the recombination effect behave as dominant gain-of-function mutations, consistent with the view that meiotic drive involves new or alien gene products. These and other data suggest that the Ab10 meiotic drive system was initially acquired from a related species and that a complex haplotype evolved around it.

Organization of the sex-ratio meiotic drive region in Drosophila simulans

4266
Montchamp-Moreau, CO, D.; Chaminade, N.; Colard, A.; Aulard, S.,  Genetics,  174:1365-1371. 2006-01-04 00:00:00.
Sex-ratio meiotic drive is the preferential transmission of the X chromosome by XY males, which occurs in several Drosophila species and results in female-biased progeny. Although the trait has long been known to exist, its molecular basis remains completely unknown. Here we report a fine-mapping experiment designed to characterize the major drive locus on a sex-ratio X chromosome of Drosophila simulans originating from the Seychelles (X-SRG). This primary locus was found to contain two interacting elements at least, both of which are required for drive expression. One of them was genetically tracked to a tandem duplication containing six annotated genes (Trf2, CG32712, CG12125, CG1440, CG12123, org-1), and the other to a candidate region located similar to 110 kb away and spanning seven annotated genes. RT-PCR showed that all but two of these genes were expressed in the testis of both sex-ratio and standard males. In situ hybridization to polytene chromosomes revealed a complete association of the duplication with the sex-ratio trait in random samples of X chromosomes from Madagascar and Reunion.

Sex-ratio meiotic drive in Drosophila simulans: cellular mechanism, candidate genes and evolution

4265
Montchamp-Moreau, C,  Biochemical Society Transactions,  34:562-565. 2006-01-03 00:00:00.
The sex-ratio trait, reported in a dozen Drosophila species, is a type of naturally occurring meiotic drive in which the driving elements are located on the X chromosome. Typically, as the result of a shortage of Y bearing spermatozoa, males carrying a sex-ratio X chromosome produce a large excess of female offspring. The presence of sex-ratio chromosomes in a species can have considerable evolutionary consequences, because they can affect individual fitness and trigger extended intragenomic conflict. Here, I present the main results of the study performed in Drosophilosimulans. In this species, the loss of Y-bearing spermatozoa is related to the inability of the Y chromosome sister-chromatids to separate properly during meiosis II. Fine genetic mapping has shown that the primary sex-ratio locus on the X chromosome contains two distorter elements acting synergistically, both of which are required for drive expression. one element has been genetically mapped to a tandem duplication. To infer the natural history of the trait, the pattern of DNA sequence polymorphism in the surrounding chromosomal region is being analysed in natural populations of D. simulans harbouring sex-ratio X chromosomes. Initial results have revealed the recent spread of a distorter allele.

Transmission ratio distortion in the human body louse, Pediculus humanus (Insecta : Phthiraptera)

4264
McMeniman, CJB, S. C.,  Heredity,  96:63-68. 2006-01-02 00:00:00.
We studied inheritance at three microsatellite loci in eight F-1 and two F-2 families of the body (clothes) louse of humans, Pediculus humanus. The alleles of heterozygous female-parents were always inherited in a Mendelian fashion in these families. Alleles from heterozygous male-parents, however, were inherited in two different ways: (i) in a Mendelian fashion and (ii) in a non-Mendelian fashion, where males passed to their offspring only one of their two alleles, that is, 100% nonrandom transmission. In male body lice, where there was non-Mendelian inheritance, the paternally inherited set of alleles was eliminated. We interpret this pattern of inheritance as evidence for extreme transmission ratio distortion of paternal alleles in this species.

An Anopheles transgenic sexing strain for vector control

16647
F. Catteruccia, J. P. Benton and A. Crisanti,  Nature Biotechnology,  23:1414-1417. 2005-10-09 20:04:20.
Here we report on the development of transgenic sexing lines for the mosquito Anopheles stephensi, the principal vector of human malaria in Asia. Male mosquitoes, expressing enhanced green fluorescent protein (EGFP) under the control of the beta 2-tubulin promoter, are identified by their fluorescent gonads in as early as their 3(rd) instar larval stage, and can be efficiently separated from females using both manual methods and automated sorting machines. Importantly, beta 2-EGFP males are not impaired in their mating ability and viable fluorescent spermatozoa are also detected in spermathecae of wild-type females mated with transgenic males. The transgenic mosquito lines described here combine most of the features desired and required for a safe application of transgenic methodologies to malariacontrol programs.

History of the Sterile Insect Technique

6360
Klassen, W. and C. F. Curtis,  Sterile Insect Technique: Principles and Practice in Area-Wide Integrated Pest Managemen,  2005:3-36.. 2005-03-09 20:56:59.
During the 1930s and 1940s the idea of releasing insects of pest species to introduce sterility (sterile insect technique or SIT) into wild populations, and thus control them, was independently conceived in three extremely diverse intellectual environments. The key researchers were A. S. Serebrovskii at Moscow State University, F. L. Vanderplank at a tsetse field research station in rural Tanganyika (now Tanzania), and E. F. Knipling of the United States Department of Agriculture. Serebrovskii’s work on chromosomal translocations for pest population suppression could not succeed in the catastrophic conditions in the USSR during World War II, after which he died. Vanderplank used hybrid sterility to suppress a tsetse population in a large field experiment, but lacked the resources to develop this method further. Knipling and his team exploited H. J. Muller’s discovery that ionizing radiation can induce dominant lethal mutations, and after World War II this approach was applied on an area-wide basis to eradicate the New World screwworm Cochliomyia hominivorax (Coquerel) in the USA, Mexico, and Central America. Since then very effective programmes integrating the SIT have been mounted against tropical fruit flies, some species of tsetse flies Glossina spp., the pink bollworm Pectinophora gossypiella (Saunders), and the codling moth Cydia pomonella (L.). In non-isolated onion fields in the Netherlands, the onion maggot Delia antiqua (Meigen) has since 1981 been suppressed by the SIT. In the 1970s there was much research conducted on mosquito SIT, which then went into “eclipse”, but now appears to be reviving. Development of the SIT for use against the boll weevil Anthonomus grandis grandis Boheman and the gypsy moth Lymantria dispar (L.) has ended, but it is in progress for two sweetpotato weevil species, Cylas formicarius (F.) and Euscepes postfasciatus (Fairmaire), the false codling moth Cryptophlebia leucotreta (Meyrick), the carob moth Ectomyelois ceratoniae (Zeller), the cactus moth Cactoblastis cactorum (Berg), the Old World screwworm Chrysomya bezziana (Villeneuve), additional Glossina spp., other Anastrepha spp. and Bactrocera spp. fruit flies, and other pest insects.

Maternal transmission ratio distortion at the mouse Om locus results from meiotic drive at the second meiotic division

4283
Wu, GMH, L. P.; Han, Z. M.; Gao, S. R.; Latham, K. E.; de Villena, F. P. M.; Sapienza, C.,  Genetics,  170:327-334. 2005-01-21 00:00:00.
We have observed maternal transmission ratio distortion (TRD) in favor of DDK alleles at the Ovum mutant (Om) locus on mouse chromosome I I among the offspring of (C57BL/6 X DDK) F, females and C57BL/6 males. Although significant lethality occurs in this backcross (similar to 50%), differences in the level of TRD found in recombinant vs. nonrecombinant chromosomes among offspring argue that TRD is due to nonrandom segregation of chromatids at the second meiotic division, i.e., true meiotic drive. We tested this hypothesis directly, by determining the centromere and Om genotypes of individual chromatids in zygote stage embryos. We found similar levels of TRD in favor of DDK alleles at Om in the female pronucleus and TRD in favor of C57BL/6 alleles at Om in the second polar body. In those embryos for which complete dyads have been reconstructed, TRD was present only in those inheriting heteromorphic dyads. These results demonstrate that meiotic drive occurs at MII and that preferential death of one genotypic class of embryo does not play a large role in the TRD.

Population dynamics of transposable elements: Copy number regulation and species invasion requirements

4282
Struchiner, CJK, M. G.; Ribeiro, J. M. C.,  Journal of Biological Systems,  13:455-475. 2005-01-20 00:00:00.
A deterministic population dynamics model of the spread of transposable elements (TE) in sexually reproducing populations is presented. The population is modeled by a three-parameter equation describing host reproductive capacity, population size and the strength of the density dependence, while TE dynamics were modeled based also on three parameters, the maximum ability of the element to copy itself in the absence of regulation (T(0)), the regulatory effect of copy number decreasing transposition (C(0.5)), and the deleterious effect of each new transposition on host fitness (d). The mechanism of transposition control is therefore a function of the number of new TE copies. Our results indicate that non-regulated elements cannot fix in host populations, and that prediction of stable copy number following successful invasion is mainly a function of the combination of T(0) and C(0.5) values. Fitness reduction does not affect the final copy number after successful invasion of the element. Fitness reduction, however, will affect the surface of the {T(0) x C(0.5)} parameter space leading to successful invasion of the TE. Invasion of host populations by eight or more individuals containing elements with appropriate parameters will lead to successful element fixation at any size of the host population. Host population extinction due to the invasion of TE's is observed in a small area of the {T(0) x C(0.5)} parameter space. These results are qualitatively preserved under alternative choices for the shape of the functions defining regulation of transposition and distinct sets of parameters determining host population dynamics.

Evidence of susceptibility and resistance to cryptic X-linked meiotic drive in natural populations of Drosophila melanogaster

4281
Reed, FAR, R. G.; Aquadro, C. F.,  Evolution,  59:1280-1291. 2005-01-19 00:00:00.
There is mounting evidence consistent with a general role of positive selection acting on the Drosophila melanogaster X-chromosome. However, this positive selection need not necessarily arise from forces that are adaptive to the organism. Nonadaptive meiotic drive may exist on the X-chromosome and contribute to forces of selection. Females from a reference D. melanogaster line, containing the X-linked marker white, were crossed to males from 49 isofemale lines established from seven African and five non-African natural populations to detect naturally occurring meiotic drive. Several lines exhibited a departure from expected Mendelian transmission of X-chromosomes to the third generation (F-2) offspring, particularly those from hybrid African male parents. F2 viability was not correlated with skewed chromosomal inheritance. However, a significant difference in viability between cosmopolitan and tropical African crosses was observed. Recombination analysis supports the presence of a male-acting meiotic drive element near the centromeric region of the X-chromosome and putative recessive autosomal drive suppression. There is also evidence of another female-acting drive element linked to white. The possible role meiotic drive may contribute in shaping levels of genetic variation in D. melanogaster, and additional ways to test this hypothesis are discussed.

Transposable element insertion location bias and the dynamics of gene drive in mosquito populations

4280
Rasgon, JLG, F.,  Insect Molecular Biology,  14:493-500. 2005-01-18 00:00:00.
Some vector-borne disease control strategies using transgenic mosquitoes require transgene spread to high frequency in populations. Transposable elements (TEs) are DNA sequences that replicate and transpose within the genomes of other organisms and may therefore be represented in the next generation in higher frequencies than predicted by Mendelian segregation. This over-representation has allowed some TEs to spread through natural populations. Transgenes incorporated within a TE sequence are expected to be driven into populations as long as there is a positive balance between fitness costs and over-representation. Models have been used to examine parameters that affect this balance but did not take into account biased insertion of TEs to linked sites in the genome. A simulation model was created to examine the impact of insertion bias on TE spread in mosquito populations. TEs that induce no fitness costs are predicted to increase in frequency over a wide range of parameter values but spread is slower for lower levels of transposition and non-local movement. If TEs are costly, high proportions of local movement can slow or halt spread. To function as a robust transgene drive mechanism a TE should replicate and transpose > 10%/insert/generation, induce < 1% fitness cost/insert, and move preferentially to unlinked sites in the genome.

Segregation distortion in hybrids between the Bogota and USA subspecies of Drosophila pseudoobscura

4279
Orr, HAI, S.,  Genetics,  169:671-682. 2005-01-17 00:00:00.
We show that, contrary to claims in the literature, "sterile" males resulting from the cross of the Bogota and USA subspecies of Drosophila pseudoobscura are weakly fertile. Surprisingly, these hybrid males produce almost all daughters when crossed to females of any genotype (pure Bogota, pure USA, hybrid F-1). Several lines of evidence suggest that this sex ratio distortion is caused by sex chromosome segregation distortion in hybrid males. We genetically analyze this normally cryptic segregation distortion and show that it involves several regions of the Bogota X chromosome that show strong epistatic interactions with each other. We further show that segregation distortion is normally masked within the Bogota subspecies by amosomal suppressors. Our analysis shows that the genetic basis of hybrid segregation distortion is similar to that of hybrid male sterility between the same subspecies. Indeed the severity of segregation distortion is correlated with the severity of sterility among hybrids. We discuss the possibility that hybrid sterility in this paradigmatic case of incipient speciation is caused by segregation distortion.

Degeneration and domestication of a selfish gene in yeast: Molecular evolution versus site-directed mutagenesis

4278
Koufopanou, VB, A.,  Molecular Biology and Evolution,  22:1535-1538. 2005-01-16 00:00:00.
VDE is a homing endonuclease gene in yeasts with an unusual evolutionary history including horizontal transmission, degeneration, and domestication into the mating-type switching locus HO. We investigate here the effects of these features on its molecular evolution. In addition, we correlate rates of evolution with results from site-directed mutagenesis studies. Functional elements have, lower rates of evolution than degenerate ones and higher conservation at functionally important sites. However, functionally important and unimportant sites are equally likely to have been involved in the evolution of new function during the domestication of VDE into HO. The domestication event also indicates that VDE has been lost in some species and that VDE has been present in yeasts for more than 50 Myr.

Meiotic drive at the Om locus in wild-derived inbred mouse strains

4277
Kim, KT, S.; Howard, I. B.; Bell, T. A.; Doherty, H. E.; Ideraabdullah, F.; Detwiler, D. A.; De Villena, F. P. M.,  Biological Journal of the Linnean Society,  84:487-492. 2005-01-15 00:00:00.
Meiotic drive is an evolutionary force in which natural selection is uncoupled from organismal fitness. Recently, it has been proposed that meiotic drive and genetic drift represent major forces in the evolution of the mammalian karyotype. Meiotic drive involves two types of genetic elements, Responders and Distorters, the latter being required to induce transmission ratio distortion at the former. We have previously described the Om meiotic drive system in mouse chromosome 11. To investigate the natural history of this drive system we have characterized the alleles present at the distorter in wild-derived inbred strains. Our analysis of transmission of maternal alleles in both classical and wild-derived inbred strains indicated that driving alleles are found at high frequency in natural populations and that the existence of driving alleles predates the split between the Mus spicilegus and M. musculus lineages. (c) 2005 The Linnean Society of London.

Genetic linkage between a sexually selected trait and X chromosome meiotic drive

4276
Johns, PMW, L. L.; Wilkinson, G. S.,  Proceedings of the Royal Society B-Biological Sciences,  272:2097-2103. 2005-01-14 00:00:00.
Previous studies on the stalk-eyed fly, Cyrtodiopsis dalmanni, have shown that males with long eye-stalks win contests and are preferred by females, and artificial selection on male relative eye span alters brood sex-ratios. Subsequent theory proposes that X-linked meiotic drive can catalyse the evolution of mate preferences when drive is linked to ornament genes. Here we test this prediction by mapping meiotic drive and quantitative trait loci (QTL) for eye span. To map QTL we genotyped 24 microsatellite loci using 1228 F2 flies from two crosses between lines selected for long or short eye span. The crosses differed by presence or absence of a drive X chromosome, X-D, in the parental male. Linkage analysis reveals that X-D dramatically reduces recombination between X and X-D chromosomes. In the X-D cross, half of the F2 males carried the drive haplotype, produced partially elongated spermatids and female-biased broods, and had shorter eye span. The largest QTL mapped 1.3 cM from drive on the X chromosome and explained 36% of the variation in male eye span while another QTL mapped to an autosomal region that suppresses drive. These results indicate that selfish genetic elements that distort the sex-ratio can influence the evolution of exaggerated traits.

Gene drive systems in mosquitoes: rules of the road

4275
James, AA,  Trends in Parasitology,  21:64-67. 2005-01-13 00:00:00.
Population replacement strategies for controlling transmission of mosquito-borne diseases call for the introgression of antipathogen effector genes into vector populations. It is anticipated that these genes, if present at high enough frequencies, will impede transmission of the target pathogens and result in reduced human morbidity and mortality. Recent laboratory successes in the development of virus- and protozoan-resistant mosquito strains make urgent research of gene drive systems capable of moving effector genes into wild populations. A systematic approach to developing safe and effective gene drive systems that includes defining the requirements of the system, identifying naturally occurring or synthetic genetic mechanisms for gene spread upon which drive systems can be based and the successful adaptation of a mechanism to a drive system, should mitigate concerns about using genetically engineered mosquitoes for disease control.

A novel meiotic drive locus almost completely distorts segregation in Mimulus (monkeyflower) hybrids

4274
Fishman, LW, J. H.,  Genetics,  169:347-353. 2005-01-12 00:00:00.
We report the discovery, mapping, and characterization of a meiotic drive locus (D) exhibiting nearly 100% nonrandom transmission in hybrids between two species of yellow monkeyflowers, outcrossing Mimulus guttatus and selfing M. nasutus. Only 1% of F-2 hybrids were M. nasutus homozygotes at the marker most tightly linked to D. We used a set of reciprocal backcrosses to distinguish among male-specific, female-specific, and zygote-specific sources of transmission ratio distortion. Transmission was severely distorted only when the heterozygous F, acted as the female parent in crosses to either parental species, ruling out pollen competition and zygote mortality as potential sources of drive. After four generations of backcrossing to M. nasutus, nearly isogenic lines were still >90% heterozygous at markers linked to D, suggesting that heterozygosity at the drive locus alone is sufficient for nonrandom transmission. A lack of dramatic female fitness costs in these lines rules out alternatives involving ovule or seed mortality and points to a truly meiotic mechanism of drive. The strength and direction of drive in this system is consistent with population genetic theory of selfish element evolution under different mating systems. These results are the first empirical demonstration of the strong female-specific drive predicted by new models of selfish centromere turnover.

Sex chromosome meiotic drive in hybrid males of the common shrew (Sorex araneus)

4273
Fedyk, SB, U.; Chetnicki, W.,  Folia Biologica-Krakow,  53:133-141. 2005-01-11 00:00:00.
Patterns of sex chromosome segregation in six homozygous males of the common Shrew (Sorex araneus LINNAEUS, 1758) belonging to two chromosomal races, as well as in 16 interracial hybrids were studied. I ascd on their karyotypes the hybrids can be subdivided into two groups: (a) complex heterozygotes, which form meiotic quadrivalents in chain and chain + ring configurations, and (b) complex heterozygotes, which Form meiotic pentavalents in chain configurations. Random 1 : 1) segregation of sex chromosomes was found ill homozygous as well as those he erozygous males which form meiotic complexes Of four chromosomes. However, in some, hybrids with meiotic pentavalents we observed a strong preferential segregation in favou of X chromosomes.

Intraparental gamete competition provides a selective advantage for the development of hybrid sterility via meiotic drive

Adams, CS,  Evolution,  59:1229-1236. 2005-01-10 00:00:00.
Hybrid sterility can have evolutionary significance and varies substantially by taxon, but few models attempt to predict or explain this variability. Hybrid sterility is commonly observed and develops early in isolation, at odds with straightforward models that predict it would develop slowly and rarely be seen. Meiotic drive might explain the rapid development of hybrid sterility, but drive is rarely observed, modifiers are expected to repress it, and no precise testable predictions are available. Here I develop population genetic models for the establishment of meiotic drive based on how it spreads by benefiting carrier gametes competing with noncarrier gametes from the same parent, or intraparental gamete competition. The resulting models predict that mciotic drive can often produce substantial hybrid sterility over time even in the presence of repressors, yet observable drive will be rare. They also make quantitative predictions of the degree of sterility based on observable parameters of reproductive ecology, including frequency of multiple mating, effective dispersal of offspring, and population size. Finally, they suggest explanations for the association of heterochromatin changes with speciation. Experimental evidence is discussed showing that drive alleles at least sometimes contribute to hybrid sterility.

TSETSE GENETICS: Contributions to Biology, Systematics, and Control of Tsetse Flies

26199
R. H. Gooding and E. S. Krafsur,  Annual Review of Entomology,  50:101-123. 2005-01-01 14:04:26.
Tsetse flies (Diptera: Glossinidae) constitute a small, ancient taxon of exclusively hematophagous insects that reproduce slowly and viviparously. Because tsetse flies are the only vectors of pathogenic African trypanosomes, they are a potent and constant threat to humans and livestock over much of sub-Saharan Africa. Despite their low fecundity, tsetse flies demonstrate great resilience, which makes population suppression expensive, transient, and beyond the capacities of private and public sectors to accomplish, except over small areas. Nevertheless, control measures that include genetic methods are under consideration at national and supranational levels. There is a pressing need for sufficient laboratory cultures of tsetse flies and financial support to carry out genetic research. Here we review tsetse genetics from organismal and population points of view and identify some research needs.

« First ‹ Previous 1 3 93 101 102 103 104 105 113 118 Next › Last »