Search results for "Genetic Variation"
showing 10 items of 836 documents
HERITABILITIES OF DOMINANCE-RELATED TRAITS IN MALE BANK VOLES (CLETHRIONOMYS GLAREOLUS)
1998
A number of studies have shown that in several animal species females prefer dominant males as mating partners, but fewer attempts have been made to measure possible indirect benefits of this choice. One reason for this may be that, even though dominance is a widely used concept, the definition of dominance still remains controversial. Furthermore, defining and measuring the heritability of social behaviors is problematic because they are not individual traits but, by definition, involve interactions between at least two individuals. In this study we estimated heritabilities and coefficients of additive genetic variances (CVA) for male traits that are closely associated with dominance and f…
Adaptive Evolution and Epigenetics
2023
Epigenetic changes, such as DNA methylation and certain histone modifications, can be inherited but in many cases they do not follow Mendelian inheritance patterns and their stability appears to be lower than for changes in DNA sequence. Adaptive evolution by natural selection requires that differences among individuals are heritable to some degree. Epigenetic changes can be incorporated into evolutionary theory, and given that properties of epigenetic variation are distinct from genetic variation, spontaneous epigenetic changes can affect evolutionary dynamics in interesting ways. In this chapter, I review the properties of epigenetic variation and how they relate to the main parameters of…
Genetic diversity in a collection of Italian long storage tomato landraces as revealed by SNP markers array
2019
Tomato (Solanum lycopersicum L.) is one of the most important crops worldwide. In this study, we used 7720 genome-wide SNPs to characterize the genetic diversity within a tomato germplasm collection enriched with 64 accessions from southern Italy of the so called "da serbo" type i.e. drought-tolerant and long storage landraces. Notwithstanding the relatively small collection area, 1575 (20.4%) polymorphic SNPs, mostly on Chr11, detected considerable levels of genetic variation. Maximum parsimony analysis of genetic distance revealed four main clusters and clearly separated most "da serbo" landraces from the outgroups. One of the clusters grouped the landraces from the Mount Vesuvius area, t…
Habitat Discontinuities Separate Genetically Divergent Populations of a Rocky Shore Marine Fish.
2016
Habitat fragmentation has been suggested to be responsible for major genetic differentiations in a range of marine organisms. In this study, we combined genetic data and environmental information to unravel the relative role of geography and habitat heterogeneity on patterns of genetic population structure of corkwing wrasse (Symphodus melops), a rocky shore species at the northern limit of its distribution range in Scandinavia. Our results revealed a major genetic break separating populations inhabiting the western and southern coasts of Norway. This genetic break coincides with the longest stretch of sand in the whole study area, suggesting habitat fragmentation as a major driver of genet…
Long-Distance Travellers: Phylogeography of a Generalist Parasite, Pholeter gastrophilus, from Cetaceans
2017
We studied the phylogeography and historical demography of the most generalist digenean from cetaceans, Pholeter gastrophilus, exploring the effects of isolation by distance, ecological barriers and hosts' dispersal ability on the population structure of this parasite. The ITS2 rDNA, and the mitochondrial COI and ND1 from 68 individual parasites were analysed. Worms were collected from seven oceanic and coastal cetacean species from the south western Atlantic (SWA), central eastern Atlantic, north eastern Atlantic (NEA), and Mediterranean Sea. Pholeter gastrophilus was considered a single lineage because reciprocal monophyly was not detected in the ML cladogram of all individuals, and seque…
High and uneven levels of 45S rDNA site-number variation across wild populations of a diploid plant genus (Anacyclus, Asteraceae)
2017
The nuclear genome harbours hundreds to several thousand copies of ribosomal DNA. Despite their essential role in cellular ribogenesis few studies have addressed intrapopulation, interpopulation and interspecific levels of rDNA variability in wild plants. Some studies have assessed the extent of rDNA variation at the sequence and copy-number level with large sampling in several species. However, comparable studies on rDNA site number variation in plants, assessed with extensive hierarchical sampling at several levels (individuals, populations, species) are lacking. In exploring the possible causes for ribosomal loci dynamism, we have used the diploid genus Anacyclus (Asteraceae) as a suitab…
Genetic variation in plasticity of life-history traits between Atlantic cod (Gadus morhua) populations exposed to contrasting thermal regimes
2016
We employed common-garden experiments to test for genetic variation in responses of larval life-history traits to temperature between two populations of Atlantic cod (Gadus morhua L., 1758) that naturally experience contrasting thermal environments during early life due to spatial and temporal differences in spawning. Southern Gulf of St. Lawrence cod larvae experienced faster growth in warmer water and low, uniform survival across all experimental temperatures (3, 7, 11 °C), consistent with previous studies on this spring-spawning population. In contrast, larvae from fall-spawning Southwestern Scotian Shelf cod collected near Sambro, Nova Scotia, lacked plasticity for growth but experienc…
Whole-genome resequencing of Cucurbita pepo morphotypes to discover genomic variants associated with morphology and horticulturally valuable traits
2019
[EN] Cucurbita pepo contains two cultivated subspecies, each of which encompasses four fruit-shape morphotypes (cultivar groups). The Pumpkin, Vegetable Marrow, Cocozelle, and Zucchini Groups are of subsp. pepo and the Acorn, Crookneck, Scallop, and Straightneck Groups are of subsp. ovifera. Recently, a de novo assembly of the C. pepo subsp. pepo Zucchini genome was published, providing insights into its evolution. To expand our knowledge of evolutionary processes within C. pepo and to identify variants associated with particular morphotypes, we performed whole-genome resequencing of seven of these eight C. pepo morphotypes. We report for the first time whole-genome resequencing of the four…
Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod
2016
AbstractIdentification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod – historically a major marine resource – Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of sev…
Origin and distribution of desert ants across the Gibraltar Straits
2017
The creation of geographic barriers has long been suspected to contribute to the formation of new species. We investigated the phylogeography of desert ants in the western Mediterranean basin in order to elucidate their mode of diversification. These insects which have a low dispersal capacity are recently becoming important model systems in evolutionary studies. We conducted an extensive sampling of species belonging to the Cataglyphis albicans group in the Iberian Peninsula (IP) and the northern Morocco (North Africa; NA). We then combined genetic, chemical and morphological analyses. The results suggest the existence of at least three and five clades in the IP and NA, respectively, whose…