Search results for "inbreeding"
showing 10 items of 137 documents
Comparing RADseq and microsatellites for estimating genetic diversity and relatedness : Implications for brown trout conservation
2019
The conservation and management of endangered species requires information on their genetic diversity, relatedness and population structure. The main genetic markers applied for these questions are microsatellites and single nucleotide polymorphisms (SNPs), the latter of which remain the more resource demanding approach in most cases. Here, we compare the performance of two approaches, SNPs obtained by restriction-site-associated DNA sequencing (RADseq) and 16 DNA microsatellite loci, for estimating genetic diversity, relatedness and genetic differentiation of three, small, geographically close wild brown trout (Salmo trutta) populations and a regionally used hatchery strain. The genetic di…
THE EFFECTS OF MATING SYSTEM AND GENETIC VARIABILITY ON SUSCEPTIBILITY TO TREMATODE PARASITES IN A FRESHWATER SNAIL, LYMNAEA STAGNALIS
2004
The amount and distribution of genetic variability in host populations can have significant effects on the outcome of host-parasite interactions. We studied the effect of mating system and genetic variability on susceptibility of Lymnaea stagnalis snails to trematode parasites. Mating system of snails from eight populations differing in the amount of genetic variability was manipulated, and self- and cross-fertilized offspring were exposed to naturally occurring trematode parasites in a controlled lake experiment. Susceptibility of snails varied between populations, but mating-system treatment did not have a significant effect. Heterozygosity of snails was negatively correlated with the pro…
Inbreeding does not alter the response to an experimental heat wave in a freshwater snail
2019
Global climate change affects natural populations of many species by increasing the average temperature and the frequency of extreme weather events (e.g. summer heat waves). The ability of organisms to cope with these environmental changes can, however, depend on their genetic properties. For instance, genetic load owing to inbreeding could alter organisms’ responses to climate change-mediated environmental changes but such effects are often overlooked. We investigated the effects of an experimental heat wave (25°C versus 15°C) on life history (reproduction, size) and constitutive immune defence traits (phenoloxidase-like and antibacterial activity of haemolymph) in relation to inbreeding b…
Luci ed ombre sull’inbreeding di animali: conservazione di caratteristiche o rischi di estinzione?
2019
Abstract esteso. Tutti i viventi sono fenotipicamente diversi ed in particolare, all’interno della stessa specie, tutti gli individui condividono alcune somiglianze e differiscono per altre caratteristiche. Solo in presenza di diversità è possibile distinguere i vari individui, è possibile per ogni individuo essere peculiare, in una sola parola, è possibile essere “unici”. È intuitivo che individui diversi hanno diversi DNA, individui simili hanno simili DNA ed individui uguali o identici (gemelli) hanno uguali DNA, almeno in sequenza primaria. L’uguaglianza genetica si può determinare anche grazie alla fedeltà di trasmissione del messaggio genetico da una generazione alla seguente, ad esem…
Absence of Sex Differential Plasticity to Light Availability during Seed Maturation in Geranium sylvaticum
2015
Sex-differential plasticity (SDP) hypothesis suggests that since hermaphrodites gain fitness through both pollen and seed production they may have evolved a higher degree of plasticity in their reproductive strategy compared to females which achieve fitness only through seed production. SDP may explain the difference in seed production observed between sexes in gynodioecious species in response to resource (nutrients or water) availability. In harsh environments, hermaphrodites decrease seed production whereas females keep it relatively similar regardless of the environmental conditions. Light availability can be also a limiting resource and thus could theoretically affect differently femal…
Species cohesion despite extreme inbreeding in a social spider.
2011
Colonial social spiders experience extreme inbreeding and highly restricted gene flow between colonies; processes that question the genetic cohesion of geographically separated populations and which could imply multiple origins from predecessors with limited gene flow. We analysed species cohesion and the potential for long-distance dispersal in the social spider Stegodyphus dumicola by studying colony structure in eastern South Africa and the cohesion between this population and Namibian populations previously published. Data from both areas were (re)analysed for historic demographic parameters. Eastern South African S. dumicola were closely related to an east Namibian lineage, showing coh…
Genome wide linkage disequilibrium and genetic structure in Sicilian dairy sheep breeds
2014
Background The recent availability of sheep genome-wide SNP panels allows providing background information concerning genome structure in domestic animals. The aim of this work was to investigate the patterns of linkage disequilibrium (LD), the genetic diversity and population structure in Valle del Belice, Comisana, and Pinzirita dairy sheep breeds using the Illumina Ovine SNP50K Genotyping array. Results Average r2 between adjacent SNPs across all chromosomes was 0.155 ± 0.204 for Valle del Belice, 0.156 ± 0.208 for Comisana, and 0.128 ± 0.188 for Pinzirita breeds, and some variations in LD value across chromosomes were observed, in particular for Valle del Belice and Comisana breeds. Ave…
No evidence for prezygotic postcopulatory avoidance of kin despite high inbreeding depression.
2018
11 pages; International audience; Offspring resulting from mating among close relatives can suffer from impaired fitness through the expression of recessive alleles with deleterious effects. Postcopulatory sperm selection (a prezygotic mechanism of cryptic female choice) has been suggested to be an effective way to avoid inbreeding. To investigate whether postcopulatory female choice allows the avoidance of fertilization by close kin, we performed artificial inseminations in a promiscuous bird, the houbara bustard (Chlamydotis undulata undulata). Females were inseminated with a mix of sperm from triads of males, each constituted of a male genetically unrelated to the female, a first cousin …
Sex-specific impact of inbreeding on pathogen load in the striped dolphin.
2020
The impact of inbreeding on fitness has been widely studied and provides consequential inference about adaptive potential and the impact on survival for reduced and fragmented natural populations. Correlations between heterozygosity and fitness are common in the literature, but they rarely inform about the likely mechanisms. Here, we investigate a pathology with a clear impact on health in striped dolphin hosts (a nematode infection that compromises lung function). Dolphins varied with respect to their parasite burden of this highly pathogenic lung nematode (Skrjabinalius guevarai). Genetic diversity revealed by high-resolution restriction-associated DNA (43 018 RADseq single nucleotide pol…
Females tend to prefer genetically similar mates in an island population of house sparrows.
2014
11 pages; International audience; BACKGROUND: It is often proposed that females should select genetically dissimilar mates to maximize offspring genetic diversity and avoid inbreeding. Several recent studies have provided mixed evidence, however, and in some instances females seem to prefer genetically similar males. A preference for genetically similar mates can be adaptive if outbreeding depression is more harmful than inbreeding depression or if females gain inclusive fitness benefits by mating with close kin. Here, we investigated genetic compatibility and mating patterns in an insular population of house sparrow (Passer domesticus), over a three-year period, using 12 microsatellite mar…