Now available ahead of print: "Allee Effects, Colonization, and Extinction: The Surprising Benefits of Demographic Stochasticity" by Angela Gong, Emma J. Walker, and Benjamin Gilbert
https://www.journals.uchicago.edu/doi/10.1086/735833
#allele #extinction #colonization #demographic #stochasticity
In a new Synthesis article, Walker & Gilbert provide a necessary framework and guide for empirical research on how allee effects structure ecological diversity. They counter a number of misconceptions about allee effects in modern coexistence theory. https://www.journals.uchicago.edu/doi/10.1086/735419
Abstract In recent years, the introduction of genetic methods to create a more disease-resistant livestock of farm animals in breeding practice increased. The studies of the genes responsible for the immune status of the organism (particularly, mannose-binding lectin 1 (MBL1) gene) are of a special importance. The frequencies of alleles and genotypes of the mannose-binding lectin 1 (MBL1) gene in Ukrainian small and transboundary cattle breeds (Lebedyn, Brown Carpathian, Jersey, Ayrshire, and Swiss) were determined by a method of PCR-RFLP testing using the HaeIII restriction enzyme (c.2569 T>C polymorphism). The determination of T- and C-alleles of the MBL1 is of a practical importance since the mannose-binding lectin gene is a candidate for markers of resistance to mastitis. The frequencies of the MBL1 T-allele in the studied breeds vary from 0.27 to 0.47, those of TC-genotypes from 0.13 to 0.4, and those of TT-genotypes from 0.17 to 0.33. In four breeds, a shift in the genetic equilibrium due to an excess of homozygotes was detected. The values of effective alleles in the MBL1 locus in the studied breeds are less than the threshold value, which indicates that the number of effective alleles in the populations for this locus is less than possible. The cow population of the endangered Brown Carpathian breed was the most polymorphic (Na = 1.993). The largest degree of realization of genetic variability was also detected in the Brown Carpathian breed (V = 41.379) (which was grown and kept in the private sector of the mountain area), and the lowest was in the Ayrshire breed (V = 13.236), respectively. The calculation of genetic distances revealed that the Jersey and Lebedyn breeds were the closest, while a maximal genetic distance was registered between animals of the Jersey and Brown Carpathian breeds. The analysis of genetic structure of the studied cattle breeds in Ukraine revealed changes in the frequency of one or another genotype depending on the breed. The results obtained in this study contain important information, which can be used in cattle breeding for resistance to mastitis.
My day job is all about #genes, so I applaud the #genomic revolution in #paleontology and #evolutionary #biology. But #evolution really is more than a shift in #allele frequencies over time. It's also change in the #phenotypes those alleles produce, and their #interaction with the world around them. 🧪🖥🧬🦖
So I'm equally excited about the #quantitative revolution in describing and cataloguing #traits which until recently could only be analyzed #qualitatively. There's a whole new window opening into the history of life.
"Une petite histoire du phénotype et de sa relation avec le génotype"
Bien que les notions de phénotype et de "relation génotype-phénotype" fassent partie du vocabulaire quotidien des biologistes, elles ne sont pas toujours bien comprises et sont parfois mal utilisées.
Dans un article de la revue du CNRS "Histoire de la recherche contemporaine", Dominique de Vienne ( #IDEEV #GQELeMoulon) retrace l’histoire de ces notions. Il rappelle d’abord que la question originelle était celle de la relation entre une variation génotypique et une variation phénotypique.
✅ En savoir plus : https://moulon.inrae.fr/news/2025/02/une-petite-histoire-du-ph%C3%A9notype-et-de-sa-relation-avec-le-g%C3%A9notype/
#phenotype #genotype #génétique #genetics #allele
#UniversitéParisSaclay @inrae_france @cnrs #gqe #dominiquedevienne
A polymorphism (g.2141C>G) of the growth hormone (GH) gene was studied in the populations of cows of the Ukrainian red-spotted dairy, Montbeliard breeds, and crossbreeds obtained from the crossing of Ukrainian red-spotted dairy cows with Montbeliard bulls, and the analysis of reproductive traits of individuals with different genotypes was conducted. Genotyping of the growth hormone gene was carried out using a PCR–RFLP method. Both L and V alleles were detected in the experimental cow populations. The ratio of the frequencies of LL/LV/VV genotypes did not differ from the theoretically expected one for each of the experimental groups (χ2 = 0.91, p < 0.05; χ2 = 1.41, p < 0.05; χ2 = 1.66, p < 0.05, respectively). In the experimental populations of the Montbeliard breed and crossbred animals, the VV genotype frequency was 0.03 and 0.06, respectively; no VV genotype was detected in the population of the Ukrainian red-spotted breed. According to the traits of reproductive function, the cows of the experimental groups with the LL genotype variant had better indices as compared with their peers with the LV genotype: an earlier age of first insemination, lower index of insemination, and shorter intercalving period. According to the live weight at birth and growth dynamics in each experimental group of cows, the carriers of the LV genotype had an advantage. Regardless of the genotype, higher indices of live weight at birth and average daily growths were established in animals of the crossbred origin as compared with purebreds. The established polymorphism of the growth hormone gene (SNP g.2141C>G) indicates a feasibility of further studies and prospect of using it as a genetic marker of reproductive ability in marker-assisted selection of dairy cattle direction of productivity.
Abstract Among a vast number of polymorphisms in the wheat genome, of special interest are those that are markers for loci under selection. Such loci include storage protein loci, which directly determine the level of bread-making quality, and disease resistance genes. In this study we analyzed diversity of functional markers (seven storage protein loci and three disease resistance genes) in the group of East European winter common wheat genotypes (cultivars and lines of Poltava breeding). Using the UPGMA or NJ methods, the cultivars and lines were divided into two clusters differing in the Glu-1 quality score. The cultivars of cluster 1 with the lower mean Glu-1 quality score predominantly carried the combination of alleles Glu-B1c, Glu-D1a, and Gli-B1e, as well as the resistance allele of Lr34, whereas those of cluster 2 with the higher quality score mainly had the alleles Glu-B1u, Glu-D1d, and Gli-B1b. In the sample of Poltava cultivars, a high correlation between the Glu-1 quality score and the sedimentation value (0.84) was observed. On average for two years, the group of cultivars from cluster 1 showed higher grain protein content and some spike traits in comparison with the means of the sample from cluster 2. Significant associations of Lr34 alleles and alleles at some storage protein loci were revealed, in particular, the association of the resistance allele Lr34R and the allele Glu-D1a in both cultivar and line groups, indicating the adaptive value of such a combination for local soil and climate conditions.
Urquhart-Cronish et al. model the eco-evolutionary range dynamics of life-history traits under density-dependent selection. They find that DD alters the extent of allele surfing & that population density is important for consequences of range expansion.
https://www.journals.uchicago.edu/doi/10.1086/728599
#evolution #densityDependent #allele #population #rangeExpansion
MathiasTCK.bsky.social
American Naturalist
Fuck Your Social Media
Cytology and Genetics
Daniel Dvorkin
GQE-Le Moulon