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The toad headed agamas (Phrynocephalus) are champions in crossing over rateтезисы доклада Тезисы
- Авторы: Lisachov A., Solovyeva E.
- Сборник: Meeting abstracts from the 11th European Cytogenetics Conference
- Тезисы
- Год издания: 2017
- Место издания: Molecular Cytogenetics
- Первая страница: 61
- Последняя страница: 61
- Аннотация: Recombination rate and crossover distribution along chromosomes vary considerably between the animal species. Several hypotheses explaining this variation were developed. However, most data on re- combination patterns were obtained from mammals. The variation in recombination is strongly dependent on karyotypic diversity of the species comprising this taxon. Squamate reptiles present a good model to study recombination due to more conservative karyotypes. Using immunolocalization of SYCP3, the protein of the axial elements of synaptonemal complex; MLH1, the mismatch-repair protein associated with the mature re- combination nodules; and the centromere proteins we investigated chromosome synapsis and recombination at pachytene in two closely related species of iguanian lizards: the toad-headed agamas Phrynocephalus guttatus and Ph. alpherakii. The karyotypes of the studied specimens consisted of 23 acrocentric bivalents: 12 pairs of macrochromosomes and 11 pairs of microchro- mosomes (2n = 46 FN = 46). Average SC length was equal to 223.9 ± 31.7 mkm (compared to 140–150 mkm in Anolis, another iguanian). We found that the toad-headed agamas show very high recombin- ation rates, on average 50.1 ± 17.5 MLH1 foci per cell (compared to 21–22 in Anolis). The distribution of the crossovers along the chro- mosomes was almost even, not showing centromere effect and inter- ference. This is in strict contrast with other vertebrates, which show prominent peaks of recombination near the telomeres and a de- crease in recombination near the centromere. This intense and evenly distributed recombination would lead to very low linkage disequilibrium in the population, efficient selection, and high genetic diversity. These lizards live in very harsh desert condi- tions. Perhaps high recombination serves to ensure efficient adapta- tion to their extreme habitat.
- Добавил в систему: Соловьева Евгения Николаевна