Tentelier C, Barroso-Gomila O, Lepais O, Manicki A, Romero-Garmendia I, Jugo B M
ECOBIOP, INRA, Univ. Pau & Pays Adour, 64310, Saint-Pée-sur-Nivelle, France.
Euskal Herriko Unibertsitatea UPV EHU, Zientzia & Teknol Fak, Genet Antropol Fis & Animalien Fisiol Saila, E-48080, Bilbao, Spain.
J Fish Biol. 2017 Apr;90(4):1644-1659. doi: 10.1111/jfb.13260. Epub 2017 Jan 18.
This study aimed to test mate choice and selection during early life stages on major histocompatibility (MH) genotype in natural families of Atlantic salmon Salmo salar spawners and juveniles, using nine microsatellites to reconstruct families, one microsatellite linked to an MH class I gene and one minisatellite linked to an MH class II gene. MH-based mate choice was only detected for the class I locus on the first year, with lower expected heterozygosity in the offspring of actually mated pairs than predicted under random mating. The genotype frequencies of MH-linked loci observed in the juveniles were compared with frequencies expected from Mendelian inheritance of parental alleles to detect selection during early life stages. No selection was detected on the locus linked to class I gene. For the locus linked to class II gene, observed heterozygosity was higher than expected in the first year and lower in the second year, suggesting overdominance and underdominance, respectively. Within family, juveniles' body size was linked to heterozygosity at the same locus, with longer heterozygotes in the first year and longer homozygotes in the second year. Selection therefore seems to differ from one locus to the other and from year to year.
本研究旨在利用9个微卫星标记重建家系，1个与MHC I类基因连锁的微卫星标记和1个与MHC II类基因连锁的小卫星标记，对大西洋鲑（Salmo salar）亲鱼和幼鱼自然家系早期生活阶段的配偶选择和基于主要组织相容性（MH）基因型的选择进行测试。仅在第一年检测到基于MHC I类基因座的配偶选择，实际配对的亲代所产后代的预期杂合度低于随机交配下的预测值。将幼鱼中观察到的与MHC连锁基因座的基因型频率与亲代等位基因孟德尔遗传预期的频率进行比较，以检测早期生活阶段的选择情况。在与MHC I类基因连锁的基因座上未检测到选择。对于与MHC II类基因连锁的基因座，第一年观察到的杂合度高于预期，第二年则低于预期，分别表明超显性和亚显性。在家庭内部，幼鱼的体长与同一基因座的杂合度相关，第一年杂合子个体较长，第二年纯合子个体较长。因此，不同基因座之间以及不同年份之间的选择似乎存在差异。
