scholarly journals Detection of Deleterious Genotypes in Multigenerational Studies. II. Theoretical and Experimental Dynamics with Selfing and Selection

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 727-737 ◽  
Author(s):  
Marjorie A Asmussen ◽  
Laura U Gilliland ◽  
Richard B Meagher
Keyword(s):  
Allelic Variation ◽  
Meiotic Drive ◽  
Genotypic Frequency ◽  
Mendelian Segregation ◽  
Experimental Dynamics ◽  
Fitness Advantage ◽  
Heterozygous Plant ◽  
Recessive Mutant ◽  
Gametic Selection

Abstract A mathematical model was developed to help interpret genotype and allele frequency dynamics in selfing populations, with or without apomixis. Our analysis provided explicit time-dependent solutions for the frequencies at diallelic loci in diploid populations under any combination of fertility, viability, and gametic selection through meiotic drive. With no outcrossing, allelic variation is always maintained under gametic selection alone, but with any fertility or viability differences, variation will ordinarily be maintained if and only if the net fitness (fertility × viability) of heterozygotes exceeds that of both homozygotes by a substantial margin. Under pure selfing and Mendelian segregation, heterozygotes must have a twofold fitness advantage; the level of overdominance necessary to preserve genetic diversity declines with apomixis, and increases with segregation distortion if this occurs equally and independently in male and female gametes. A case study was made of the Arabidopsis act2-1 actin mutant over multiple generations initiated from a heterozygous plant. The observed genotypic frequency dynamics were consistent with those predicted by our model for a deleterious, incompletely recessive mutant in either fertility or viability. The theoretical framework developed here should be very useful in dissecting the form(s) and strength of selection on diploid genotypes in populations with negligible levels of outcrossing.

scholarly journals Wolbachia -induced meiotic drive and feminization is associated with an independent occurrence of selective mitochondrial sweep in a butterfly

2017 ◽  
Vol 13 (5) ◽  
pp. 20170153 ◽  
Author(s):  
Mai Miyata ◽  
Tatsuro Konagaya ◽  
Kenji Yukuhiro ◽  
Masashi Nomura ◽  
Daisuke Kageyama
Keyword(s):  
Selective Sweep ◽  
Cytoplasmic Incompatibility ◽  
Meiotic Drive ◽  
Sequence Polymorphism ◽  
The Other ◽  
Considerable Proportion ◽  
Evolutionary Forces ◽  
Eurema Hecabe ◽  
Hybrid Introgression

Maternally inherited Wolbachia endosymbionts manipulate arthropod reproduction in various ways. In the butterfly Eurema mandarina , a cytoplasmic incompatibility-inducing Wolbachia strain w CI and the associated mtDNA haplotypes are known to originate from the sister species Eurema hecabe , which offered a good case study for microbe-mediated hybrid introgression. Besides w CI, some females with the Z0 karyotype harbour a distinct Wolbachia strain w Fem, which causes all-female production by meiotic drive and feminization. We report that a considerable proportion of E. mandarina females (65.7%) were infected with both w CI and w Fem (CF) on Tanegashima Island. While females singly infected with w CI (C) produced offspring at a 1 : 1 sex ratio, CF females produced only females. Although Z-linked sequence polymorphism showed no signs of divergence between C and CF females, mtDNA split into two discrete clades; one consisted of C females and the other CF females, both of which formed a clade with E. hecabe but not with uninfected E. mandarina . This suggests that CF matrilines also, but independently, experienced a selective sweep after hybrid introgression from E. hecabe . Distinct evolutionary forces were suggested to have caused C and CF matrilines to diverge, which would be irreversible because of the particular phenotype of w Fem.

scholarly journals A pooled sequencing approach identifies a candidate meiotic driver in Drosophila

2017 ◽  
Author(s):  
Kevin H-C Wei ◽  
Hemakumar M. Reddy ◽  
Chandramouli Rathnam ◽  
Jimin Lee ◽  
Deanna Lin ◽  
...  
Keyword(s):  
Telomere Length ◽  
Natural Populations ◽  
Meiotic Drive ◽  
Length Variation ◽  
Sequence Evolution ◽  
Nucleotide Polymorphisms ◽  
Mendelian Segregation ◽  
Transmission Frequency ◽  
Multiple Observations ◽  
Telomere Sequence

AbstractMeiotic drive occurs when a selfish element increases its transmission frequency above the Mendelian ratio by hijacking the asymmetric divisions of female meiosis. Meiotic drive causes genomic conflict and potentially has a major impact on genome evolution, but only a few drive loci of large effect have been described. New methods to reliably detect meiotic drive are therefore needed, particularly for discovering moderate-strength drivers that are likely to be more prevalent in natural populations than strong drivers. Here we report an efficient method that uses sequencing of large pools of backcross (BC1) progeny to test for deviations from Mendelian segregation genome-wide of single-nucleotide polymorphisms (SNPs) that distinguish the parental strains. We show that meiotic drive can be detected by a characteristic pattern of decay in distortion of SNP frequencies, caused by recombination unlinking the driver from distal loci. We further show that control crosses allow allele-frequency distortion caused by meiotic drive to be distinguished from distortion resulting from developmental effects. We used this approach to test whether chromosomes with extreme telomere-length differences segregate at Mendelian ratios, as telomeric regions are a potential hotspot for meiotic drive due to their roles in meiotic segregation and multiple observations of high rates of telomere sequence evolution. Using four different pairings of long and short telomere strains, we find no evidence that extreme telomere-length variation causes meiotic drive in Drosophila. However, we identify one candidate meiotic driver in a centromere-linked region that shows an ~8% increase in transmission frequency, corresponding to a ~54:46 segregation ratio. Our results show that candidate meiotic drivers of moderate strength can be readily detected and localized in pools of F1 progeny.

scholarly journals Habitat-Specific Clock Variation and Its Consequence on Reproductive Fitness

2019 ◽  
Vol 35 (2) ◽  
pp. 134-144
Author(s):  
Bala S. C. Koritala ◽  
Craig Wager ◽  
Joshua C. Waters ◽  
Ryan Pachucki ◽  
Benedetto Piccoli ◽  
...  
Keyword(s):  
Circadian Clock ◽  
Allelic Variation ◽  
Reproductive Fitness ◽  
Tree Bark ◽  
Oxygen Species ◽  
Fitness Advantage ◽  
Fitness Trait ◽  
Cellular Reactive Oxygen Species ◽  
Type Strains ◽  
Constant Dark

The circadian clock controls daily activities at the cellular and organismic level, allowing an organism to anticipate incoming stresses and to use resources accordingly. The circadian clock has therefore been considered a fitness trait in multiple organisms. However, the mechanism of how circadian clock variation influences organismal reproductive fitness is still not well understood. Here we describe habitat-specific clock variation (HSCV) of asexual reproduction in Neurospora discreta, a species that is adapted to 2 different habitats, under or above tree bark. African (AF) N. discreta strains, whose habitat is above the tree bark in light-dark (LD) conditions, display a higher rhythmicity index compared with North American (NA) strains, whose habitat is under the tree bark in constant dark (DD). Although AF-type strains demonstrated an overall fitness advantage under LD and DD conditions, NA-type strains exhibit a habitat-specific fitness advantage in DD over the LD condition. In addition, we show that allelic variation of the clock-controlled gene, Ubiquinol cytochrome c oxidoreductase (NEUDI_158280), plays a role in HSCV by modulating cellular reactive oxygen species levels. Our results demonstrate a mechanism by which local adaptation involving circadian clock regulation influences reproductive fitness.

scholarly journals Epistatic selection on a selfish Segregation Distorter supergene: drive, recombination, and genetic load

2021 ◽  
Author(s):  
Beatriz Navarro-Dominguez ◽  
Ching-Ho Chang ◽  
Cara Brand ◽  
Christina Muirhead ◽  
Daven Presgraves ◽  
...  
Keyword(s):  
Genetic Load ◽  
Meiotic Drive ◽  
Fruit Fly ◽  
Common Mechanism ◽  
Mendelian Segregation ◽  
Chromosomal Structure ◽  
Synonymous Mutations ◽  
Segregation Distorter ◽  
History Of ◽  
Chromosome Variant

Meiotic drive supergenes are complexes of alleles at linked loci that together subvert Mendelian segregation to gain preferential transmission. In males, the most common mechanism of drive involves the disruption of sperm bearing alternative alleles. While at least two loci are important for male drive- the driver and the target- linked modifiers can enhance drive, creating selection pressure to suppress recombination. In this work, we investigate the evolution and genomic consequences of an autosomal multilocus, male meiotic drive system, Segregation Distorter (SD) in the fruit fly, Drosophila melanogaster. In African populations, the predominant SD chromosome variant, SD-Mal, is characterized by two overlapping, paracentric inversion on chromosome arm 2R and nearly perfect (~100%) transmission. We study the SD-Mal system in detail, exploring its components, chromosomal structure, and evolutionary history. Our findings reveal a recent chromosome-scale selective sweep mediated by strong epistatic selection for haplotypes carrying Sd, the main driving allele, and one or more factors within the double inversion. While most SD-Mal chromosomes are homozygous lethal, SD-Mal haplotypes can recombine with other, complementing haplotypes via crossing over and with wildtype chromosomes only via gene conversion. SD-Mal chromosomes have nevertheless accumulated lethal mutations, excess non-synonymous mutations, and excess transposable element insertions. Therefore, SD-Mal haplotypes evolve as a small, semi-isolated subpopulation with a history of strong selection. These results may explain the evolutionary turnover of SD haplotypes in different populations around the world and have implications for supergene evolution broadly.

COMPONENTS OF SELECTION IN X CHROMOSOME LINES OF DROSOPHILA MELANOGASTER: SEX RATIO MODIFICATION BY MEIOTIC DRIVE AND VIABILITY SELECTION

Genetics ◽  
1984 ◽  
Vol 108 (4) ◽  
pp. 941-952
Author(s):  
James W Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Maximum Likelihood ◽  
Sex Ratio ◽  
Genetic Background ◽  
Likelihood Estimation ◽  
Meiotic Drive ◽  
Mendelian Segregation ◽  
Viability Selection ◽  
Naturally Occurring

ABSTRACT Selection coefficients and segregation parameters have been estimated in 18 randomly chosen lines carrying wild Χ chromosomes on the cn bw genetic background. Each line was studied in replicated crosses of four types, with approximately 100 replications per line per cross. Crosses in which male Χ chromosomes differed exhibited significant sex ratio heterogeneity. Maximum likelihood estimation of segregation parameters revealed two lines in which the proportion of Χ-bearing gametes produced by males was significantly different from Mendelian expectations. These observations suggest that segregation distortion is a common feature of naturally occurring genetic variation. Non-Mendelian segregation has important evolutionary implications.

scholarly journals ON THE COMPONENTS OF SEGREGATION DISTORTION IN DROSOPHILA MELANOGASTER. III. NATURE OF ENHANCER OF SD

Genetics ◽  
1984 ◽  
Vol 107 (3) ◽  
pp. 423-434
Author(s):  
John G Brittnacher ◽  
Barry Ganetzky
Keyword(s):  
Drosophila Melanogaster ◽  
Segregation Distortion ◽  
Allelic Variation ◽  
Meiotic Drive ◽  
Dependent Manner ◽  
X Ray ◽  
Segregation Distorter ◽  
In Cis ◽  
General Component

ABSTRACT Analysis of X-ray-induced deletions in the Segregation Distorter (SD) chromosome, SD-5, revealed that this chromosome had a gene proximal to lt in the centric heterochromatin of 2L that strongly enhanced the meiotic drive caused by the SD chromosome. This Enhancer of Segregation Distortion [E(SD)] locus had not been characterized in earlier studies of SD chromosomes because it cannot be readily separated by recombination from the Responder (Rsp) locus in the proximal heterochromatin of 2R.—To determine whether E(SD) is a general component of all SD chromosomes and to examine further its effects on distortion, we produced deletions of E(SD) in three additional SD chromosomes. Analysis of these deletions leads to the following conclusions: (1) along with Sd and Rsp, E(SD) is common to all SD chromosomes; (2) the E(SD) allele on each SD chromosome enhances distortion by the same amount, which indicates that allelic variation at the E(SD) locus is not responsible for the different drive strengths seen among SD chromosomes; (3) E(SD) causes very little or no distortion by itself in the absence of Sd; (4) E(SD), like Sd, acts in a dosage-dependent manner; (5) E(SD) exerts its effect in cis or trans to Sd; and (6) if E(SD)  + exists, its function is not related to SD.

scholarly journals DISTORTED MENDELIAN INHERITANCE OF THE FUSED VEIN TRAIT IN CUCURBITA PEPC L.: A CASE FOR GAMETIC SELECTION

HortScience ◽  
1992 ◽  
Vol 27 (11) ◽  
pp. 1161b-1161
Author(s):  
R. Bruce Carle ◽  
J. Brent Loy
Keyword(s):  
Mendelian Inheritance ◽  
Pollen Competition ◽  
Central Vein ◽  
Significant Heterogeneity ◽  
Chi Square ◽  
Mendelian Segregation ◽  
Leaf Trait ◽  
Low Levels ◽  
Gametic Selection ◽  
Chi Square Analysis

The recessive leaf trait, fused vein (fv), in Cucurbita pepo L. is expressed by the sixth leaf stage and then throughout vegetative growth. It is characterized by the partial fusion of the lateral leaf veins to the main central vein. Consequently, the dorsal leaf surface is distinctively puckered. Use of fv as a genetic marker in hull-less seeded pumpkin lines is hampered, however, by a low recovery of fv plants in segregating populations. Homogeneity Chi Square analysis of 11 F2 (3:1 X2 = 72.05 P < 0.005) and 16 BC (1:1 X2 = 120.12 P < 0.005) populations indicated significant heterogeneity between populations for fv recovery. Recovery ranged from 0 to 35.5% for 11 F2 populations and from 6.8 to 75.4% for 16 BC populations. There was a significant reduction, 35%, in seed yield/fruit when fv pollen was used to hand pollinate fv, normal (N), and F1 flowers as compared to pollinations with N pollen. In pollen competition studies, reduced competition at low levels of F1 or 50:50 fv/N pollen increased fv recovery in F2 and BC populations. These results are consistent with the hypothesis that the fv trait confers gametic subvitality resulting in distorted Mendelian segregation.

scholarly journals Non-Mendelian Segregation of Sex Chromosomes in Heterospecific Drosophila Males

Genetics ◽  
2000 ◽  
Vol 154 (2) ◽  
pp. 687-694 ◽  
Author(s):  
Emmanouil T Dermitzakis ◽  
John P Masly ◽  
Heidi M Waldrip ◽  
Andrew G Clark
Keyword(s):  
Sex Ratio ◽  
Sex Chromosome ◽  
Recombinant Inbred Lines ◽  
Meiotic Drive ◽  
Drosophila Genome ◽  
Hybrid Male ◽  
Mendelian Segregation ◽  
Hybrid Male Sterility ◽  
Two Factors ◽  
Biased Sex Ratio

Abstract Interspecific hybrids and backcrossed organisms generally suffer from reduced viability and/or fertility. To identify and genetically map these defects, we introgressed regions of the Drosophila sechellia genome into the D. simulans genome. A female-biased sex ratio was observed in 24 of the 221 recombinant inbred lines, and subsequent tests attributed the skew to failure of Y-bearing sperm to fertilize the eggs. Apparently these introgressed lines fail to suppress a normally silent meiotic drive system. Using molecular markers we mapped two regions of the Drosophila genome that appear to exhibit differences between D. simulans and D. sechellia in their regulation of sex chromosome segregation distortion. The data indicate that the sex ratio phenotype results from an epistatic interaction between at least two factors. We discuss whether this observation is relevant to the meiotic drive theory of hybrid male sterility.

Sign in / Sign up

Export Citation Format

Share Document