scholarly journals X-linked meiotic drive can boost population size and persistence

Genetics ◽  
2020 ◽  
Vol 217 (1) ◽  
pp. 1-11
Author(s):  
Carl Mackintosh ◽  
Andrew Pomiankowski ◽  
Michael F Scott
Keyword(s):  
Population Size ◽  
Sex Ratios ◽  
Meiotic Drive ◽  
Population Level ◽  
Male Mating ◽  
Genetic Elements ◽  
Selfish Genetic Elements ◽  
Sex Ratio Bias ◽  
Ejaculate Size ◽  
Male Mating Behavior

Abstract X-linked meiotic drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased sex ratios. Here, we find general conditions for the spread and fixation of X-linked alleles. Our conditions show that the spread of X-linked alleles depends on sex-specific selection and transmission rather than the time spent in each sex. Applying this logic to meiotic drive, we show that polymorphism is heavily dependent on sperm competition induced both by female and male mating behavior and the degree of compensation to gamete loss in the ejaculate size of drive males. We extend these evolutionary models to investigate the demographic consequences of biased sex ratios. Our results suggest driving X-alleles that invade and reach polymorphism (or fix and do not bias segregation excessively) will boost population size and persistence time by increasing population productivity, demonstrating the potential for selfish genetic elements to move sex ratios closer to the population-level optimum. However, when the spread of drive causes strong sex-ratio bias, it can lead to populations with so few males that females remain unmated, cannot produce offspring, and go extinct. This outcome is exacerbated when the male mating rate is low. We suggest that researchers should consider the potential for ecologically beneficial side effects of selfish genetic elements, especially in light of proposals to use meiotic drive for biological control.

scholarly journals X-linked meiotic drive boosts population size and persistence

2020 ◽  
Author(s):  
Carl Mackintosh ◽  
Andrew Pomiankowski ◽  
Michael F Scott
Keyword(s):  
Extinction Risk ◽  
Sex Ratios ◽  
Full Range ◽  
Meiotic Drive ◽  
Population Level ◽  
Genetic Elements ◽  
Selfish Genetic Elements ◽  
Population Sizes ◽  
Selection For ◽  
Male Carriers

ABSTRACTX-linked meiotic drivers cause X-bearing sperm to be produced in excess by male carriers, leading to female-biased sex ratios. Selection for these selfish sex chromosomes can lead to completely female populations, which cannot produce offspring and go extinct. However, at the population level, moderately female-biased sex ratios are optimal because relatively few males are required to fertilise all the females. We develop eco-evolutionary models for sex-linked meiotic drive alleles to investigate their full range of demographic effects. We find general conditions for the spread and fixation of X-drivers, accounting for transmission bias and other factors associated with the spread of X-drivers such as sperm competition and polyandry. Our results suggest driving X-alleles that do not reach fixation (or do not bias segregation excessively) will boost population sizes and persistence times by increasing population productivity, demonstrating the potential for selfish genetic elements to move sex ratios closer to the population-level optimum. We suggest that researchers should look beyond extinction risk and consider the potential for ecologically beneficial side effects of selfish genetic elements, especially in light of proposals to use meiotic drive for biological control.

scholarly journals Transposable element control disrupted by meiotic drive in a stalk-eyed fly genome

2020 ◽  
Author(s):  
Josephine A Reinhardt ◽  
Richard H. Baker ◽  
Aleksey V. Zimin ◽  
Chloe Ladias ◽  
Kimberly A Paczolt ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Transposable Element ◽  
X Chromosome ◽  
Meiotic Drive ◽  
Genetic Elements ◽  
Selfish Genetic Elements ◽  
Genome Defense ◽  
Genomic Divergence ◽  
Pirna Pathway ◽  
Female Carriers

AbstractSome stalk-eyed flies in the genus Teleopsis carry selfish genetic elements that induce sex ratio (SR) meiotic drive and impact the fitness of male and female carriers. Here, we produce a chromosome-level genome assembly of the stalk-eyed fly, T. dalmanni, to elucidate the pattern of genomic divergence associated with the presence of drive elements. We find evidence for multiple nested inversions along the sex ratio haplotype and widespread differentiation and divergence between the inversion types along the entire X chromosome. In addition, the genome contains tens of thousands of transposable element (TE) insertions and hundreds of transcriptionally active TE families that have produced new insertions. Moreover, we find that many TE families are expressed at a significantly higher level in SR male testis, suggesting a molecular connection between these two types of selfish genetic elements in this species. We identify T. dalmanni orthologs of genes involved in genome defense via the piRNA pathway, including core members maelstrom, piwi and Argonaute3, that are diverging in sequence, expression or copy number between the SR and standard (ST) chromosomes, and likely influence TE regulation in flies carrying a sex ratio X chromosome.

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 Social structure and demography of a remnant Asian elephant Elephas maximus population and the implications for survival

Oryx ◽  
2020 ◽  
pp. 1-6
Author(s):  
Lauren J. Hale ◽  
Kun Shi ◽  
Tania C. Gilbert ◽  
Kelvin S.-H. Peh ◽  
Philip Riordan
Keyword(s):  
Social Structure ◽  
Population Size ◽  
Total Population ◽  
Camera Traps ◽  
Asian Elephant ◽  
Elephas Maximus ◽  
Effective Density ◽  
Anthropogenic Pressures ◽  
Sex Ratio Bias ◽  
Elephant Population

Abstract The Asian elephant Elephas maximus is at risk of extinction as a result of anthropogenic pressures, and remaining populations are often small and fragmented remnants, occupying a fraction of the species' former range. Once widely distributed across China, only a maximum of 245 elephants are estimated to survive across seven small populations. We assessed the Asian elephant population in Nangunhe National Nature Reserve in Lincang Prefecture, China, using camera traps during May–July 2017, to estimate the population size and structure of this genetically important population. Although detection probability was low (0.31), we estimated a total population size of c. 20 individuals, and an effective density of 0.39 elephants per km2. Social structure indicated a strong sex ratio bias towards females, with only one adult male detected within the population. Most of the elephants associated as one herd but three adult females remained separate from the herd throughout the trapping period. These results highlight the fragility of remnant elephant populations such as Nangunhe and we suggest options such as a managed metapopulation approach for their continued survival in China and more widely.

scholarly journals Infertility and Male Mating Behavior Deficits Associated With Pde1c in Drosophila melanogaster

Genetics ◽  
2010 ◽  
Vol 186 (1) ◽  
pp. 159-165 ◽  
Author(s):  
David B. Morton ◽  
Rachel Clemens-Grisham ◽  
Dennis J. Hazelett ◽  
Anke Vermehren-Schmaedick
Keyword(s):  
Drosophila Melanogaster ◽  
Mating Behavior ◽  
Male Mating ◽  
Male Mating Behavior

Population size structure and sex ratios in some woodlice (Crustacea: Oniscidae) from southern Africa

1994 ◽  
Vol 10 (2) ◽  
pp. 261-271 ◽  
Author(s):  
J. M. Dangerfield ◽  
S. R. Telford
Keyword(s):  
Population Size ◽  
Southern Africa ◽  
Life Histories ◽  
Mating Systems ◽  
Size Structure ◽  
Sex Ratios ◽  
Interspecific Variation ◽  
Sexual Competition ◽  
Population Size Structure ◽  
Adult Sex Ratio

ABSTRACTThe population size structure and adult sex ratio were recorded for four indigenous and one introduced species of terrestrial isopod from southern Africa. Interspecific variation was considerable with either discrete or continuous distributions indicative of the production of separate cohorts or continuous recruitment. Intraspecific variation was also considerable particularly in species such as Aphiloscia vilis which can be found in diverse habitats. Sex ratios were consistently female biased, a result consistent with observations made on temperate species. These observations, and a consideration of sexual dimorphism based on body mass, suggest that phenotypic plasticity may be an important tactic in the life histories of tropical woodlice and that in some populations the potential exists for strong sexual competition and complex mating systems.

scholarly journals Does segregating variation in sexual or microhabitat preferences lead to non-random mating within a population of Drosophila melanogaster ?

2009 ◽  
Vol 6 (1) ◽  
pp. 102-105 ◽  
Author(s):  
Brad R. Foley ◽  
Anne Genissel ◽  
Harmon L. Kristy ◽  
Sergey V. Nuzhdin
Keyword(s):  
Recombinant Inbred Lines ◽  
Random Mating ◽  
Population Level ◽  
Inbred Lines ◽  
Male Mating ◽  
Complex Environment ◽  
Level Variation ◽  
Group Preference ◽  
Female Genotype ◽  
Microhabitat Preferences

Variation in female choice for mates has implications for the maintenance of genetic variation and the evolution of male traits. Yet, estimates of population-level variation in male mating success owing to female genotype are rare. Here, we used a panel of recombinant inbred lines to estimate the strength of selection at many genetic loci in a single generation and attempt to assess differences between females with respect to the males they mated with. We performed selection assays in a complex environment to allow differences in habitat or social group preference to be expressed. We detected directional selection at loci across the genome, but are unable to provide support for differential male success because of variation in female genotype.

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