scholarly journals Sex Chromosome Meiotic Drive in Stalk-Eyed Flies

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1169-1180 ◽  
Author(s):  
Daven C Presgraves ◽  
Emily Severance ◽  
Gerald S Willrinson
Keyword(s):  
Sex Ratio ◽  
Sex Chromosome ◽  
Sex Ratios ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Operational Sex Ratio ◽  
Genetic Modifiers ◽  
Ratio Distortion ◽  
The Impact ◽  
Sex Ratio Distortion

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 stalk-eyed flies, Cyrtodiopsis dalmanni and C. whitei, are due to a meiotic drive element on the X chromosome (Xd). Relatively high frequencies of Xd in C. dalmanni and C. whitei (13–17% and 29%, respectively) cause female-biased sex ratios in natural populations of both species. Sex ratio distortion is associated with spermatid degeneration in male carriers of Xd. Variation in sex ratios is caused by Y-linked and autosomal factors that decrease the intensity of meiotic drive. Y-linked polymorphism for resistance to drive exists in C. dalmanni in which a resistant Y chromosome reduces the intensity and reverses the direction of meiotic drive. When paired with Xd, modifying Y chromosomes (Ym) cause the transmission of predominantly Y-bearing sperm, and on average, production of 63% male progeny. The absence of sex ratio distortion in closely related monomorphic outgroup species suggests that this meiotic drive system may predate the origin of C. whitei and C. dalmanni. We discuss factors likely to be involved in the persistence of these sex-linked polymorphisms and consider the impact of Xd on the operational sex ratio and the intensity of sexual selection in these extremely sexually dimorphic flies.

scholarly journals Resistance to meiotic drive at the MD locus in an Indian wild population of Aedes aegypti

1977 ◽  
Vol 29 (2) ◽  
pp. 123-132 ◽  
Author(s):  
S. G. Suguna ◽  
R. J. Wood ◽  
C. F. Curtis ◽  
A. Whitelaw ◽  
S. J. Kazmi
Keyword(s):  
Sex Ratio ◽  
Aedes Aegypti ◽  
Genetic Control ◽  
Wild Population ◽  
Sex Ratios ◽  
Meiotic Drive ◽  
In The Wild ◽  
Ratio Distortion ◽  
Sex Ratio Distortion ◽  
Different Parts

SUMMARYFemales from an Indian wild population of Aedes aegypti were crossed to males carrying the sex ratio distorter factor MD which shows meiotic drive. Progenies from F1 males were tested for sex ratio distortion, i.e. the chromosomes from the wild females were screened for their resistance to the action of MD. The distribution of sex ratio in the progenies of different F1 males indicated a polymorphism in the wild population for resistant and sensitive variants of the X chromosome. Seven discrete categories of X appear to exist, associated with sex ratios ranging from 50% ♀ to less than 1·25% ♀. The overall level of resistance varied slightly but significantly in different parts of a town. The results are discussed in relation to the use of sex ratio distortion for genetic control of mosquitoes.

scholarly journals EXPERIMENTAL POPULATION GENETICS OF MEIOTIC DRIVE SYSTEMS. III. NEUTRALIZATION OF SEX-RATIO DISTORTION IN DROSOPHILA THROUGH SEX-CHROMOSOME ANEUPLOIDY

Genetics ◽  
1981 ◽  
Vol 98 (2) ◽  
pp. 317-334
Author(s):  
Terrence W Lyttle
Keyword(s):  
Sex Ratio ◽  
Y Chromosome ◽  
Sex Chromosome ◽  
Meiotic Drive ◽  
Generation Model ◽  
Sex Chromosome Aneuploidy ◽  
Population Extinction ◽  
Chromosome Aneuploidy ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

ABSTRACT Laboratory populations of Drosophila melanogaster were challenged by pseudo-Y drive, which mimics true Y-chromosome meiotic drive through the incorporation of Segregation Distorter (SD) in a T(Y;2) complex. This causes extreme sex-ratio distrotion and can ultimately lead to population extinction. Populations normally respond by the gradual accumulation of drive suppressors, and this reduction in strength of distortion allows the sex ratio to move closer to the optimal value of 1:1. One population monitored, however, was rapidly able to neutralize the effects of sex-ratio distortion by the accumulation of sex-chromosome aneuploids (XXY, XYY). This apparently occurs because XX-bearing eggs, produced in relatively high numbers (~4%) by XXY genotypes, become the main population source of females under strong Y-chromosome drive. Computer simulation for a discrete generation model incorporating random mating with differences in fitness and segregation permits several predictions that can be compared to the data. First, sex-chromosome aneuploids should rapidly attain equilibrium, while stabilizing the population at ~60% males. This sex ratio should be roughly independent of the strength of the meiotic drive. Moreover, conditions favoring the accumulation of drive suppressors (e.g., weak distortion, slow population extinction) are insufficient for maintaining aneuploidy, while conditions favoring aneuploidy (e.g., strong distortion, low production of females) lead to population extinction before drive suppressors can accumulate. Thus, the different mechanisms for neutralizing sex-ratio distortion are complementary. In addition, Y drive and sex-chromosome aneuploidy are potentially co-adaptive, since under some conditions neither will survive alone. Finally, these results suggest the possibility that genetic variants promoting sex-chromosome nondisjunction may have a selective advantage in natural populations faced with sex-ratio distortion.

scholarly journals Sex Ratios in a Warming World: Thermal Effects on Sex-Biased Survival, Sex Determination, and Sex Reversal

2021 ◽  
Vol 112 (2) ◽  
pp. 155-164
Author(s):  
Suzanne Edmands
Keyword(s):  
High Temperature ◽  
Sex Ratio ◽  
Sex Determination ◽  
Heat Tolerance ◽  
Sex Ratios ◽  
Sex Reversal ◽  
Survival Sex ◽  
Ratio Distortion ◽  
Warming World ◽  
Sex Ratio Distortion

Abstract Rising global temperatures threaten to disrupt population sex ratios, which can in turn cause mate shortages, reduce population growth and adaptive potential, and increase extinction risk, particularly when ratios are male biased. Sex ratio distortion can then have cascading effects across other species and even ecosystems. Our understanding of the problem is limited by how often studies measure temperature effects in both sexes. To address this, the current review surveyed 194 published studies of heat tolerance, finding that the majority did not even mention the sex of the individuals used, with <10% reporting results for males and females separately. Although the data are incomplete, this review assessed phylogenetic patterns of thermally induced sex ratio bias for 3 different mechanisms: sex-biased heat tolerance, temperature-dependent sex determination (TSD), and temperature-induced sex reversal. For sex-biased heat tolerance, documented examples span a large taxonomic range including arthropods, chordates, protists, and plants. Here, superior heat tolerance is more common in females than males, but the direction of tolerance appears to be phylogenetically fluid, perhaps due to the large number of contributing factors. For TSD, well-documented examples are limited to reptiles, where high temperature usually favors females, and fishes, where high temperature consistently favors males. For temperature-induced sex reversal, unambiguous cases are again limited to vertebrates, and high temperature usually favors males in fishes and amphibians, with mixed effects in reptiles. There is urgent need for further work on the full taxonomic extent of temperature-induced sex ratio distortion, including joint effects of the multiple contributing mechanisms.

Variation in Y chromosome meiotic drive in Aedes aegypti (Diptera: Culicidae): a potential genetic approach to mosquito control

1997 ◽  
Vol 87 (6) ◽  
pp. 617-623 ◽  
Author(s):  
K. O. Owusu-Daaku ◽  
R. J. Wood ◽  
R. D. Butler
Keyword(s):  
Sex Ratio ◽  
Aedes Aegypti ◽  
Y Chromosome ◽  
Reciprocal Cross ◽  
Mosquito Control ◽  
Meiotic Drive ◽  
Genetic Approach ◽  
Single Form ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

AbstractReciprocal 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 Fl, in which the Y chromosome may or may not show meiotic drive against the X chromosome with which it is paired. The pattern of inheritance is not in agreement with a single form of Y chromosome, driving with different degrees of intensity against Xs of different sensitivity, but indicates different forms of driving Y chromosome. A rule has emerged that if Fl males from any cross give rise to a male distorted sex ratio in their progeny (F2), the males from the reciprocal cross give rise to a normal sex ratio. All eleven newly colonized strains from Ghana showed Y meiotic drive against the Xs of five strains, one of American and four of Australian origin, although one of the eleven showed a greater degree of drive than the other ten against the same sensitive strains. The variation observed is discussed in relation to previous studies on meiotic drive by the MD haplotype, and to the possible exploitation of sex ratio distortion in controlling this potentially dangerous insect.

scholarly journals SEX RATIO DISTORTION CAUSED BY MEIOTIC DRIVE IN A MOSQUITO, Culex pipiens L

Genetics ◽  
1978 ◽  
Vol 88 (3) ◽  
pp. 427-446
Author(s):  
Theresa Luine Sweeny ◽  
A Ralph Barr
Keyword(s):  
Sex Ratio ◽  
Chromosome Pair ◽  
Culex Pipiens ◽  
Recessive Gene ◽  
Meiotic Drive ◽  
Female Offspring ◽  
Large Excess ◽  
Daughter Cells ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

ABSTRACT A genetic factor, distorter (d), has been discovered that upsets the normal sex ratio of 1:1 and results in a large excess of males in Culex pipiens. The effect can be explained by a sex-linked, recessive gene. Males homozygous for the gene (Md/md) produce few female offspring; the effect is not due to postzygotic mortality. During the first meiotic division in spermatogenesis, the shortest chromosome pair, which, according to Jost and Laven (1971), is associated with sex determination, can be seen to be abnormal. In a high proportion of spermatocysts, one of the dyads of the shortest bivalent fragments, and the pieces are distributed irregularly to the daughter cells. It is believed that the female-determining chromosomes fragment. This would give rise to an excess of male-determining sperm. The possible usefulness of this factor for control or for experimental purposes is discussed.

Sex-Ratio Distortion Caused by Meiotic Drive in Mosquitoes

1991 ◽  
Vol 137 (3) ◽  
pp. 379-391 ◽  
Author(s):  
Roger J. Wood ◽  
Martha E. Newton
Keyword(s):  
Sex Ratio ◽  
Meiotic Drive ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

scholarly journals Sex-ratio distortion in Drosophila simulans: co-occurence of a meiotic drive and a suppressor of drive

1995 ◽  
Vol 8 (3) ◽  
pp. 283-300 ◽  
Author(s):  
Herve Mercot ◽  
Anne Atlan ◽  
Micheline Jacques ◽  
Catherine Montchamp-Moreau
Keyword(s):  
Sex Ratio ◽  
Meiotic Drive ◽  
Drosophila Simulans ◽  
Ratio Distortion ◽  
Sex Ratio Distortion

scholarly journals Patterns and Mechanisms of Sex Ratio Distortion in the Collaborative Cross Mouse Mapping Population

2021 ◽  
Author(s):  
Brett A Haines ◽  
Francesca Barradale ◽  
Beth L Dumont
Keyword(s):  
Sex Ratio ◽  
Sex Determination ◽  
Sex Chromosome ◽  
Collaborative Cross ◽  
Mouse Population ◽  
Genetic Conflict ◽  
Mendelian Expectation ◽  
Ratio Distortion ◽  
Sex Ratio Distortion ◽  
Sex Biases

In species with single-locus chromosome-based mechanisms of sex determination, the laws of segregation predict an equal ratio of females to males at birth. Here, we show that departures from this Mendelian expectation are commonplace in the 8-way recombinant inbred Collaborative Cross (CC) mouse population. More than one-third of CC strains exhibit significant sex ratio distortion (SRD) at wean, with twice as many male-biased than female-biased strains. We show that these pervasive sex biases persist across multiple breeding environments, are stable over time, are not fully mediated by maternal effects, and are not explained by sex-biased neonatal mortality. SRD exhibits a heritable component, but QTL mapping analyses and targeted investigations of sex determination genes fail to nominate any large effect loci. These findings, combined with the reported absence of sex ratio biases in the CC founder strains, suggest that SRD manifests from multilocus combinations of alleles only uncovered in recombined CC genomes. We speculate that the genetic shuffling of eight diverse parental genomes during the early CC breeding generations led to the decoupling of sex-linked drivers from their co-evolved suppressors, unleashing complex, multiallelic systems of sex chromosome drive. Consistent with this interpretation, we show that several CC strains exhibit copy number imbalances at co-evolved X- and Y-linked ampliconic genes that have been previously implicated in germline genetic conflict and SRD in house mice. Overall, our findings reveal the pervasiveness of SRD in the CC population and nominate the CC as a powerful resource for investigating sex chromosome genetic conflict in action.

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