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.
Male sterility and meiotic drive associated with sex chromosome rearrangements in Drosophila: Role of X-Y pairing
Tags: Gene drive mechanisms, Other arthropods, Transmission distortionMcKee, BDW, K.; Merrill, C.; Ren, X. J., Genetics, 149:143-155. 1998.
In Drosophila melanogaster, deletions of the pericentromeric X heterochromatin cause X-Y nondisjunction, reduced male fertility and distorted sperm recovery ratios (meiotic drive) in combination with a normal Y chromosome and interact with Y-autosome translocations (T(Y;A)) to ...
Segregation distortion in myotonic dystrophy
Tags: Gene drive mechanisms, Other mammals, Transmission distortionMagee, ACH, A. E., Journal of Medical Genetics, 35:1045-1046. 1998.
Myotonic dystrophy (DM) is an autosomal dominant disease which, in the typical pedigree, shows a three generation anticipation cascade. This results in infertility and congenital myotonic dystrophy (CDM) with the disappearance of DM in that pedigree. The concept of segregation ...
Sex ratio distortion in Acraea encedon (Lepidoptera : Nymphalidae) is caused by a male-killing bacterium
Tags: Evolution, Gene drive, Transmission distortionJiggins, FMH, G. D. D.; Majerus, M. E. N., Heredity, 81:87-91. 1998.
Females of the butterfly Acraea encedon produce either entirely female offspring or males and females in an almost 1:1 sex ratio. The sex ratio produced is maternally inherited and was previously attributed to sex chromosome meiotic drive. We report that all-female lineages are ...
Selfish genes and meiotic drive
Tags: Gene drive, Transmission distortionHurst, LD, Nature, 391:223-223. 1998.
Work by Gerald Wilkinson and colleagues3 on stalk-eyed flies (Diopsidae), described on page 276, provides the strongest evidence to date about the nature of some of the genes females prefer. As their name suggests, stalk-eyed flies have their eyes perched on the end of ...
Selfish genetic elements and speciation
Tags: EvolutionHurst, GDDS, M., Heredity, 80:2-8. 1998.
This review concerns the importance of selfish genetic elements (SGEs) in speciation. We assess the importance of medea genes, meiotic drive elements, transposable elements and the bacterium Wolbachia in the creation of postzygotic isolation. Although all of these elements can ...
Identification of the t complex-encoded cytoplasmic dynein light chain Tctex1 in inner arm I1 supports the involvement of flagellar dyneins in meiotic drive
Tags: Fruit fly, Gene drive mechanisms, Other mammalsHarrison, AO-C, P.; King, S. M., Journal of Cell Biology, 140:1137-1147. 1998.
The cytoplasmic dynein light chain Tctex1 is a candidate for one of the distorter products involved in the non-Mendelian transmission of mouse t haplotypes. It has been unclear, however, how the t-specific mutations in this protein, which is found associated with cytoplasmic ...
Malaria: existing methods of vector control and molecular entomology
Tags: Gene drive synthetic, Other arthropodsCurtis, CFT, H., British Medical Bulletin, 54:311-325. 1998.
In general, the most effective means of malaria vector control is the killing of adult mosquitoes with a residual insecticide applied to bednets or sprayed on house walls and ceilings. Major reductions in all-cause child mortality have been achieved in Africa by these means. In ...
Wolbachia as a possible means of driving genes into populations
Tags: Gene drive, Gene drive mechanisms, Other arthropods, WolbachiaCurtis, CFS, S. P., Parasitology, 116:S111-S115. 1998.
Cytoplasmic incompatibility consists of sterility in cross matings, the crossing type being maternally inherited. It can be explained by the action of Wolbachia symbionts which are transmitted through the egg cytoplasm and leave an imprint on the sperm which prevents it ...
Localization of the genes controlling B chromosome transmission rate in maize (Zea mays ssp. mays, Poaceae)
Tags: Chromosomal drive, Gene drive mechanismsChiavarino, AMR, M.; Rosi, P.; Poggio, L.; Naranjo, C. A., American Journal of Botany, 85:1581-1585. 1998.
In previous papers we found that the frequency of B chromosomes in native races of maize varies considerably in different populations. Moreover, we found genotypes that control high and low transmission rates (TR) of B chromosomes in the Pisingallo race. In the present work ...
Selfish DNA and breeding system in flowering plants
Tags: Chromosomal drive, Gene drive, Population genetics/dynamics, Selfish genetic elementsBurt, AT, R., Proceedings of the Royal Society B-Biological Sciences, 265:141-146. 1998.
In many species, some individuals carry one or more B chromosomes: extra, or supernumerary chromosomes not part of the normal complement. In most well-studied cases, B's lower the fitness of their carrier and persist in populations only because of accumulation mechanisms ...
Putting the brake on drive: meiotic drive of t haplotypes in natural populations of mice
Tags: Fruit fly, Gene drive mechanismsArdlie, KG, Trends in Genetics, 14:189-193. 1998.
Mouse t haplotypes are a 'selfish' form of chromosome 17 that show non-mendelian transmission from heterozygous +/t males. The considerable transmission bias in favour of t haplotypes should result in very high frequencies of these chromosomes in natural populations, but they ...
Polymorphism for Y-linked suppressors of sex-ratio in two natural populations of Drosophila mediopunctata
Tags: Gene drive mechanisms, Other arthropods, X chromosomeCarvalho, ABV, S. C.; Klaczko, L. B., Genetics, 146:891-902. 1997.
In several Drosophila species there is a trait known as ''sex-ratio'': males carrying certain X chromosomes (called ''SR'') produce female biased progenies due to X-Y meiotic drive. In Drosophila mediopunctata this trait has a variable expression due to Y-linked suppressors of ...
Identification of a male meiosis-specific gene, Tcte2, which is differentially spliced in species that form sterile hybrids with laboratory mice and deleted in t chromosomes showing meiotic drive
Tags: Fruit fly, Gene drive mechanisms, Other mammalsBraidotti, GB, D. P., Developmental Biology, 186:85-99. 1997.
Tcte2 (t complex testes expressed 2) is a male meiosis-specific gene that maps to band 3.3 of mouse chromosome 17. Two distinct male fertility defects, hybrid sterility and transmission ratio distortion, have previously been mapped to this region. Hybrid sterility arises in ...
The sex-ratio trait in Drosophila simulans: Geographical distribution of distortion and resistance
Tags: Gene drive mechanisms, Other arthropods, X chromosomeAtlan, AM, H.; Landre, C.; Montchamp-Moreau, C., Evolution, 51:1886-1895. 1997.
The sex-ratio trait we describe here in Drosophila simulans results from X-linked meiotic drive. Males bearing a driving X chromosome can produce a large excess of females (about 90%) in their progeny. This is, however, rarely the case in the wild, where resistance factors, ...
Non-Mendelian transmission at the Machado-Joseph disease locus in normal females: Preferential transmission of alleles with smaller CAG repeats
Tags: Gene drive mechanisms, Other mammals, Transmission distortionRubinsztein, DCL, J., Journal of Medical Genetics, 34:234-236. 1997.
Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3, is a neurodegenerative disorder which is associated with a CAG repeat expansion in the MJD1 gene on chromosome 14q32.1. A recent study reported an excess of transmission of disease chromosomes relative to ...
Sex chromosome meiotic drive in stalk-eyed flies
Tags: Evolution, Gene drive mechanisms, Other arthropods, Transmission distortion, X chromosomePresgraves, DCS, E.; Wilkinson, G. S., Genetics, 147:1169-1180. 1997.
Meiotically driven sex chromosomes can quickly spread to fixation and cause population extinction unless balanced by selection or suppressed by genetic modifiers. We report results of genetic analyses that demonstrate that extreme female-biased sex ratios in two sister species of ...
Variation in Y chromosome meiotic drive in Aedes aegypti (Diptera: Culicidae): a potential genetic approach to mosquito control
Tags: Gene drive mechanisms, MosquitoesOwusuDaaku, KOW, R. J.; Butler, R. D., Bulletin of Entomological Research, 87:617-623. 1997.
Reciprocal crosses between strains of Aedes aegypti (Linnaeus) from different geographical areas have revealed an unexpectedly complex pattern of holandrically inherited male biased sex ratios in F2. The variation has been interpreted in terms of a web of X-Y interactions in F1, ...
Selected lines of Aedes aegypti with persistently distorted sex ratios
Tags: Ecology, Gene drive mechanisms, Transmission distortion, Y-chromosomeOwusuDaaku, KOW, R. J.; Butler, R. D., Heredity, 79:388-393. 1997.
A breeding scheme to isolate X chromosomes sensitive to drive by the T8 (Trinidad) Y chromosome of Aedes aegypti (the MD haplotype) is reported. Crosses with an Australian strain Th.I (Thursday Island) revealed not only sensitive and resistant X chromosomes but also some with the ...
Abnormal spermiogenesis is associated with the X-linked sex-ratio trait in Drosophila simulans
Tags: Other arthropods, Transmission distortionMontchampMoreau, CJ, D., Heredity, 79:24-30. 1997.
The sex-ratio trait, known in several Drosophila species, results from X-linked meiotic drive that affects Y-bearing sperm and causes males to produce female-biased progeny. We describe spermiogenesis in three types of D, simulans males: wild-type, sex-ratio, and males that bear ...
Meiotic drive at the myotonic dystrophy and the cone-rod dystrophy loci on chromosome 19q13.3
Tags: Gene drive mechanisms, Other mammalsInglehearn, CFG, C. Y., American Journal of Human Genetics, 60:1562-1563. 1997.
The apparently conflicting observations of a high new mutation rate at the myotonic dystrophy (DM) locus on chromosome 19q13.3 and of a founder effect for DM chromosomes led researchers to invoke the influence of meiotic drive at this locus. Two studies (Carey et al. 1994; ...
Segregation distortion in unstructured and structured populations: Competition between ‘sterile’ t haplotypes
Tags: Fruit fly, Rodents, Transmission distortionVanBoven, MW, F. J., Netherlands Journal of Zoology, 46:216-226. 1996.
By means of two simple models we investigate the competition between sex-specific segregation distorters in unstructured and structured populations. The models are motivated by the t complex of the house mouse. Some variants at this gene complex, the t haplotypes, distort ...
Competition between segregation distorters: Coexistence of ”superior” and ”inferior” haplotypes at the t complex
Tags: Evolution, Fruit fly, Gene drive mechanisms, Rodents, Transmission distortionvanBoven, MW, F. J.; Heg, D.; Huisman, J., Evolution, 50:2488-2498. 1996.
By means of population genetical models, we investigate the competition between sex-specific segregation distorters. Although the models are quite general, they are motivated by a specific example, the t complex of the house mouse. Some variants at this gene complex, the t ...
Genetic control of B chromosome transmission rate in Zea mays ssp mays (Poaceae)
Tags: Chromosomal drive, Gene drive mechanismsRosato, MC, A. M.; Naranjo, C. A.; Puertas, M. J.; Poggio, L., American Journal of Botany, 83:1107-1112. 1996.
We selected genotypes of high and low B chromosome transmission rate (TR) in a native race of maize (Pisingallo) from northwest Argentina. We made 20 female 0B x male 1B and 20 f.1B x m.0B crosses. The former (G0m) showed a large variation of B TR, with a mean of TR +/- SE = 0.52 ...
Measuring meiotic drive
Tags: Gene drive mechanismsRobbins, LGP, G.; Bonaccorsi, S.; Pimpinelli, S., Genetics, 142:645-647. 1996.
LAURENCE HURST’S (1996) letter re-examines our data on the effect of Stellate copy number on the meiotic parameters of Mystal- (= su(ste)-) males (PALUMBO et al. 1994). In our analysis, we found a tight correlation of fertility and disjunction with Stellate copy number, with ...
Meiotic drive in fungi: Chromosomal elements that cause fratricide and distort genetic ratios
Tags: Ecology, Gene drive mechanisms, Toxin-antidote, Transmission distortionRaju, NB, Journal of Genetics, 75:287-296. 1996.
Fungal Spore killers (Sk), studied most extensively in Neurospora and to a lesser extent in Podospora, Gibberella and Cochliobolus, cause the death of ascospores (= meiospores) that do not contain the killer (Sk(K)) element. When a Spore killer is heterozygous (Sk(K) x Sk(S)) in ...
Epistatic control of non-mendelian inheritance in mouse interspecific crosses
Tags: Gene drive mechanisms, Other mammals, Transmission distortionMontagutelli, XT, R.; Nadeau, J. H., Genetics, 143:1739-1752. 1996.
Strong deviation of allele frequencies from Mendelian inheritance favoring Mus spretus-derived alleles has been described previously for X-linked loci in four mouse interspecific crosses. We reanalyzed data for three of these crosses focusing on the location of the gene(s) ...
The effect of B chromosomes on mating success of the grasshopper Eyprepocnemis plorans
Tags: Chromosomal drive, Ecology, Other arthropodsMartin, SA, P.; HenriquesGil, N., Genetica, 97:197-203. 1996.
The mating ability of E. plorans was tested in laboratory conditions in six experimental units composed of ten males and fifteen females during 31 days. When significant differences were found (three from the six cages, and in totals) they involved a decrease of matings involving ...
Analysis of meiotic segregation, using single-sperm typing: Meiotic drive at the myotonic dystrophy locus
Tags: Other mammals, Transmission distortionLeeflang, EPM, M. S.; Arnheim, N., American Journal of Human Genetics, 59:896-904. 1996.
Meiotic drive at the myotonic dystrophy (DM) locus has recently been suggested as being responsible for maintaining the frequency, in the human population, of DM chromosomes capable of expansion to the disease state. In order to test this hypothesis, we have studied samples of ...
The mouse t-complex-encoded protein Tctex-1 is a light chain of brain cytoplasmic dynein
Tags: Fruit fly, Other mammals, Transmission distortionKing, SMD, J. F.; Benashski, S. E.; Lye, R. J.; PatelKing, R. S.; Pfister, K. K., Journal of Biological Chemistry, 271:32281-32287. 1996.
Mammalian brain cytoplasmic dynein contains three light chains of M(r) = 8,000, 14,000, add 22,000 (King, S. M., Barbarese, E., Dillman, J. F., III, Patel-King, R. S., Carson, J. H., and Pfister, K. Kr (1996) J. Biol. Chem. 271, 19358-19366). Peptide sequence data (16/16 residues ...
Further evidence consistent with Stellate’s involvement in meiotic drive
Tags: Gene drive mechanisms, Other arthropods, Transmission distortionHurst, LD, Genetics, 142:641-643. 1996.
STELLATE is an X-linked multicopy gene found in Drosophila melanogaster and is one of the most bizarre gene arrays yet described (for details see HARDY et al. 1984; LIVAK 1984, 1990; DANILEVSKAYA et al. 1991; BAW~REVA et al. 1992; SHEVELYOV 1992; PALUMBO et al. 1994). The ...
Evidence for B chromosome drive suppression in the grasshopper Eyprepocnemis plorans
Tags: Chromosomal drive, Other arthropods, Transmission distortionHerrera, JAL, M. D.; Cabrero, J.; Shaw, M. W.; Camacho, J. P. M., Heredity, 76:633-639. 1996.
The grasshopper Eyprepocnemis plorans is polymorphic for both a B chromosome and a heterochromatic segment of chromatin on the smallest autosome. Females transmit these to their offspring more frequently after copulating with a male from a population without Bs than after ...
Segregation distortion of the CTG repeats at the myotonic dystrophy locus
Tags: Gene drive, Gene drive mechanisms, Other mammalsChakraborty, RS, D. N.; Deka, R.; Yu, L. M.; Shriver, M. D.; Ferrell, R. E., American Journal of Human Genetics, 59:109-118. 1996.
Myotonic dystrophy (DM), an autosomal dominant neuromuscular disease, is caused by a CTG-repeat expansion, with affected individuals having greater than or equal to 50 repeats of this trinucleotide, at the DMPK locus of human chromosome 19q13.3. Severely affected individuals die ...
The inheritance of B chromosomes in Allium schoenoprasum L
Tags: Chromosomal drive, Gene drive mechanismsBougourd, SMP, A. B., Chromosome Research, 4:151-158. 1996.
The inheritance of B chromosomes has been investigated in Allium schoenoprasum from the River Wye, Powys; controlled crosses between plants of known B chromosome constitution were carried out, and the numbers of Bs present in the progenies scored. There was considerable ...
Low frequency of mouse t haplotypes in wild populations is not explained by modifiers of meiotic drive
Tags: Fruit fly, Gene drive mechanismsArdlie, KGS, L. M., Genetics, 144:1787-1797. 1996.
t haplotypes are naturally occurring forms of mouse chromosome 17 that show non-Mendelian transmission from heterozygous +/t males. In laboratory studies, transmission ratios of greater than or equal to 0.90 or higher are typically observed. With transmission ratios of this ...
Gene transfer into the Medfly, Ceratitis capitata, using a Drosophila hydei transposable element.
Tags: Fruit fly, Gene drive synthetic, Gene editing, Selfish genetic elementsT. G. Loukeris, I. Livadaras, B. Arca, S. Zabalou and C. Savakis, Science, 270:2002-2005. 1995.
Exogenous functional DNA was introduced into the germline chromosomes of the Mediterranean fruit fly (medfly) Ceratitis capitata with a germline transformation system based on the transposable element Minos from Drosophila hydei. Transformants were identified as phenotypic ...
Meiotic drive in female mice: An essay
Tags: Evolution, Rodents, Transmission distortionRuvinsky, A, Mammalian Genome, 6:315-320. 1995.
Since the rediscovery of Mendel's laws, geneticists have accumulated various examples in which equal meiotic segregation in heterozygotes is violated. However, only a few natural meiotic drive systems have been characterized in detail and the majority of these are sex chromosome ...
Sex-ratio distortion in Drosophila simulans – cooccurrence of a meiotic drive and a suppressor of drive
Tags: Evolution, Gene drive mechanisms, Transmission distortion, X chromosomeMercot, HA, A.; Jacques, M.; Montchampmoreau, C., Journal of Evolutionary Biology, 8:283-300. 1995.
A sex-ratio distortion factor was found at high frequency in D. simulans strains from Seychelles and New Caledonia. This factor is poorly or not expressed within those strains which are resistant to it. Its presence was detected by crossing females from New Caledonia or the ...
Tctex2 – a sperm tail surface protein mapping to the t-complex
Tags: Fruit fly, Other mammalsHuw, LYG, A. S.; Willison, K.; Artzt, K., Developmental Biology, 170:183-194. 1995.
Transmission ratio distortion (TRD) in mouse t-haplotypes remains the most significant example of meiotic drive in vertebrates. While the underlying mechanism that fuels it is still mysterious, TRD is clearly a complex multigene phenomenon. The characterization of Tctex2 ...
Meiotic drive an Myotonic Dystrophy – Reply
Tags: Evolution, Gene drive, Gene drive mechanisms, Other mammalsCarey, NJ, K.; Nokelainen, P.; Peltonen, L.; Savontaus, M. L.; Juvonen, V.; Anvret, M.; Grandell, U.; Chotai, K.; Robertson, E.; Middletonprice, H.; Malcolm, S., Nature Genetics, 10:133-133. 1995.
Myotonic dystrophy (DM) is a trinucleotide disorder and in sub-clinical individuals there is considerable variation in the length of the CTG repeat. Two groups have recently analysed the patterns of segregation of different sized alleles at this locus and both report an excess of ...
Ascoycete spore killers: Chromosomal elements that distort genetic ratios among the products of meiosis
Tags: Gene drive mechanisms, Toxin-antidote, Transmission distortionRaju, NB, Mycologia, 86:461-473. 1994.
Spore killers (Sk), studied most extensively in Neurospora, are also known in Podospora, Gibberella and Cochliobolus. Spore killers are no doubt present in natural populations of other fungi. Criteria are outlined here for recognizing their presence and distinguishing them from ...
Characterization of 2 Segregation Distorter revertants: Evidence that the tandem duplication is necessary for SD activity in Drosophila melanogaster
Tags: Gene drive mechanisms, Transmission distortionPalopoli, MFD, P.; Wu, C. I., Genetics, 136:209-215. 1994.
Segregation Distorter (SD) is a naturally occurring system of meiotic drive in Drosophila melanogaster. Males heterozygous for an SD second chromosome and a normal homolog (SD+) transmit predominantly SD-bearing sperm. To accomplish this, the Segregation distorter (Sd) locus ...
Functional identification of the Segregation Distorter locus of Drosophila melanogaster by germline transformation
Tags: Gene drive mechanisms, Other arthropods, Transmission distortionMcLean, JRM, C. J.; Powers, P. A.; Ganetzky, B., Genetics, 137:201-209. 1994.
Segregation Distorter (SD) is a meiotic drive system in D. melanogaster that results in the failure of SD/SD+ males to transmit SD+ homologs owing to the induced dysfunction of spermatids carrying the normal chromosome. Segregation distorter (Sd), the gene primarily responsible ...
Selfish DNA as method of pest control
Tags: Gene drive mechanisms, Gene drive syntheticHastings, IM, Philosophical Transactions of the Royal Society B-Biological Sciences, 344:313-324. 1994.
The inheritance of most genes is tightly controlled, governed by the rules of mendelian inheritance if nuclear or uniparental inheritance if cytoplasmic. A few notable genes and cytoplasmic genomes have escaped this regulation. Such genes may spread by increasing their own rate ...
Meiotic drive at the myotonic dystrophy locus
Tags: Evolution, Gene drive, Gene drive mechanisms, Other mammals, Transmission distortionGennarelli, MD, B.; Baiget, M.; Martorell, L.; Novelli, G., Journal of Medical Genetics, 31:980-980. 1994.
The mutation underlying myotonic dystrophy (DM, MIM* 160900) is the expansion of a CTG trinucleotide repeat sequence at the 3' untranslated region of a protein kinase gene (MT-PK).' The kinetics of this process is influenced by the sex of the transmitting parent and size of the ...
Y-linked suppressors of the sex-ratio trait in Drosophila mediopunctata
Tags: Gene drive mechanisms, Other arthropods, X chromosomeDecarvalho, ABK, L. B., Heredity, 73:573-579. 1994.
X-linked meiotic drive causing female-biased progenies is known to occur in nine Drosophila species and is called 'sex-ratio'. In D. mediopunctata this trait is associated with the X:21 chromosome inversion and has variable expression. We describe here a powerful Y-linked ...
The evolution of lethals in the t-haplotype system of the mouse
Tags: Evolution, Fruit fly, Gene drive mechanisms, Other mammalsCharlesworth, B, Proceedings of the Royal Society B-Biological Sciences, 258:101-107. 1994.
The evolution of lethal haplotypes in the t-haplotype segregation distortion system of Mus is examined by mathematical and computer models. The models assume that there is reproductive compensation for the loss of lethal embryos, such that the net reproductive success of a female ...
Hypothetical sisterkiller
Tags: Evolution, Toxin-antidoteButcher, DLD, H. W., Nature, 369:26-26. 1994.
It was premature of Hurst in his News and Views article I to accept Haig's claim2 that a hypothetical meiotic drive element, SisterKiller, can lead to evolution from one-step to multi-step meiosis. The basis of Haig's claim is that a SisterKiller allele that causes a gamete to ...
Bewildering Bs – An impression of the 1st B-chromosome conference
Tags: Birds, Chromosomal drive, Other arthropods, Other mammalsBeukeboom, LW, Heredity, 73:328-336. 1994.
Ever since their first discovery B chromosomes have attracted attention. Why are they so appealing? The standard chromosomes of an organism are A chromosomes; B chromosomes are extra to this normal complement. In the B chromosome 'bible' (Jones & Rees, 1982) Bs are defined as ...
Eradication of the screwworm from Libya using the sterile insect technique
Tags: Sterile insect technique (SIT)M. Vargas-Terán, B. S. Hursey and E. P. Cunningham, Parasitology Today, 10:119-122. 1994.
The introduction in 1988 of the New World screwworrn into Libya presented a serious threat to the livestock and wildlife sectors of the African continent Mediterranean and the region. In this article, MoisPs Vargas-Terin, Brian 8. Hursey and Edward P. Cunningham describe the ...
The Segregation Distorter (SD) complex and the accumulation of deleterious genes in laboratory strains of Drosophila melanogaster
Tags: Evolution, Gene drive mechanisms, Other arthropods, Transmission distortionDominguez, AS, E.; Albornoz, J.; Gutierrez, A., Theoretical and Applied Genetics, 87:479-486. 1993.
Segregation Distorter (SD) associated with the second chromosome of D. melanogaster is found in nature at equilibrium frequencies lower than 5%. We report extremely high frequencies of SD (30-50%) in two selected strains, established in 1976, and show it to be responsible for the ...
