Search results for " depression"

Viability selection creates negative heterozygosity–fitness correlations in female Black Grouse Lyrurus tetrix

2017

There is widespread interest in the relationship between individual genetic diversity and fitness–related traits (heterozygosity–fitness correlations, HFC). Most studies found weak continuous increases of fitness with increasing heterozygosity while negative HFC have rarely been reported. Negative HFC are expected in cases of outbreeding depression and outbreeding is rare in natural populations; but negative HFC may also arise through viability selection acting on low heterozygosity individuals at an early stage producing a skew in the heterozygosity distribution leading to negative HFCs. We tested this idea using survival and clutch parameters (egg mass, egg volume, chick mass, clutch size…

Odor diversity decreases with inbreeding in the antHypoponera opacior

2016

Reduction in heterozygosity can lead to inbreeding depression. This loss of genetic variability especially affects diverse loci, such as immune genes or those encoding recognition cues. In social insects, nestmates are recognized by their odor, that is their cuticular hydrocarbon profile. Genes underlying hydrocarbon production are thought to be under balancing selection. If so, inbreeding should result in a loss of chemical diversity. We show here that cuticular hydrocarbon diversity decreases with inbreeding. Studying an ant with a facultative inbreeding lifestyle, we found inbred workers to exhibit both a lower number of hydrocarbons and less diverse, that is less evenly proportioned pro…

2016

Most large mammals have constantly been exposed to anthropogenic influence over decades or even centuries. Because of their long generation times and lack of sampling material, inferences of past population genetic dynamics, including anthropogenic impacts, have only relied on the analysis of the structure of extant populations. Here, we investigate for the first time the change in the genetic constitution of a natural red deer population over two centuries, using up to 200-year-old antlers (30 generations) stored in trophy collections. To the best of our knowledge, this is the oldest DNA source ever used for microsatellite population genetic analyses. We demonstrate that government policy …

Inbreeding reveals mode of past selection on male reproductive characters in Drosophila melanogaster

2013

Directional dominance is a prerequisite of inbreeding depression. Directionality arises when selection drives alleles that increase fitness to fixation and eliminates dominant deleterious alleles, while deleterious recessives are hidden from it and maintained at low frequencies. Traits under directional selection (i.e., fitness traits) are expected to show directional dominance and therefore an increased susceptibility to inbreeding depression. In contrast, traits under stabilizing selection or weakly linked to fitness are predicted to exhibit little-to-no inbreeding depression. Here, we quantify the extent of inbreeding depression in a range of male reproductive characters and then infer t…

2021

Molecular and morphological data suggest weak phylogeographic structure in the fairy shrimp Streptocephalus torvicornis (Branchiopoda, Anostraca)

2017

Inland aquatic organisms almost ubiquitously display a pattern of marked provincialism characterized by substantial population differentiation and genealogical discontinuities. This is the result of strong priority effects and local adaptation following dispersal and colonization of new habitats. We present a case that defies this biogeographic paradigm. We have investigated the phylogeography of the fairy shrimp Streptocephalus torvicornis across its circum-Mediterranean and Eurasian distribution. Based on three independent datasets, namely sequence variation at 12S and 16S rRNA, cyst morphology and male second antenna characters, we discern a pattern of extensive genetic and morphological…

Risk of inbreeding : problem of mate choice and fitness effects?

2016

Mating with close kin may cause inbreeding depression with negative consequences to offspring and local populations. There exist mechanisms like kin-recognition or sex-specific dispersal to avoid mating with kin. In fluctuating population densities, like in many small mammals, both very low and very high densities provide conditions for inbreeding, if kin males are prone to stay in their natal area. Females are choosy and male dominance is thought to be the key feature when selecting mating partners. The aim of this study was to test the possible discrepancy in mate choice and negative fitness effects of inbreeding in two experiments, one in the laboratory and one in field enclosures. We as…

No inbreeding depression in sperm storage ability or offspring viability in Drosophila melanogaster females.

2013

Mating between relatives usually decreases genetic quality of progeny as deleterious recessive alleles are expressed in inbred individuals. Inbreeding degrades sperm traits but its effects on sperm storage and fate within females are currently unknown. We quantified the relationship between the degrees of inbreeding relevant to natural populations (f=0, 0.25 and 0.50) and the number of sperm inseminated and stored, sperm swimming speed, long-term sperm viability while in storage, pattern of sperm precedence, mating latency, and offspring viability of female Drosophila melanogaster. The use of transgenic flies that have either red or green fluorescent sperm heads allowed us to distinguish tw…

Heterozygosity-fitness correlations in adult and juvenile Zenaida Dove, Zenaida aurita.

2013

10 pages; International audience; Understanding how fitness is related to genetic variation is of crucial importance in both evolutionary ecology and conservation biology. We report a study of heterozygosity-fitness correlations in a wild, noninbred population of Zenaida Doves, Zenaida aurita, based on a sample comprising 489 individuals (382 adults and 107 juveniles) typed at 13 microsatellite loci, resulting in a data set comprising 5793 genotypes. In both adults and juveniles, and irrespective of sex, no evidence was found for an effect of either multilocus or single-locus heterozygosity on traits potentially related to fitness such as foraging tactic, competitive ability, and fluctuatin…

Effects of inbreeding on a gregarious parasitoid wasp with complementary sex determination

2017

Inbreeding and inbreeding depression are processes in small populations of particular interest for a range of human activities such as animal breeding, species conservation or pest management. In particular, biological control programs should benefit from a thorough understanding of the causes and consequences of inbreeding because natural enemies experience repetitive bottlenecks during importation, laboratory rearing, and introduction. Predicting the effect of inbreeding in Hymenopteran parasitoid wasps, frequently used in biological control programs, is nonetheless a difficult endeavor. In haplodiploid parasitoids, the purge of deleterious alleles via haploid males should reduce genetic …