TY - JOUR

T1 - Heterochiasmy and sexual dimorphism

T2 - The case of the barn swallow (hirundo rustica, hirundinidae, aves)

AU - Malinovskaya, Lyubov P.

AU - Tishakova, Katerina

AU - Shnaider, Elena P.

AU - Borodin, Pavel M.

AU - Torgasheva, Anna A.

PY - 2020/10

Y1 - 2020/10

N2 - Heterochiasmy, a sex-based difference in recombination rate, has been detected in many species of animals and plants. Several hypotheses about evolutionary causes of heterochiasmy were proposed. However, there is a shortage of empirical data. In this paper, we compared recombination related traits in females and males of the barn swallow Hirundo rustica (Linnaeus, 1758), the species under strong sexual selection, with those in the pale martin Riparia diluta (Sharpe and Wyatt, 1893), a related and ecologically similar species with the same karyotype (2N = 78), but without obvious sexual dimorphism. Recombination traits were examined in pachytene chromosome spreads prepared from spermatocytes and oocytes. Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins, correspondingly. Recombination rate was significantly higher (p = 0.0001) in barn swallow females (55.6 ± 6.3 recombination nodules per autosomal genome), caused by the higher number of nodules at the macrochromosomes, than in males (49.0 ± 4.5). They also showed more even distribution of recombination nodules along the macrochromosomes. At the same time, in the pale martin, sexual differences in recombination rate and distributions were rather small. We speculate that an elevated recombination rate in the female barn swallows might have evolved as a compensatory reaction to runaway sexual selection in males.

AB - Heterochiasmy, a sex-based difference in recombination rate, has been detected in many species of animals and plants. Several hypotheses about evolutionary causes of heterochiasmy were proposed. However, there is a shortage of empirical data. In this paper, we compared recombination related traits in females and males of the barn swallow Hirundo rustica (Linnaeus, 1758), the species under strong sexual selection, with those in the pale martin Riparia diluta (Sharpe and Wyatt, 1893), a related and ecologically similar species with the same karyotype (2N = 78), but without obvious sexual dimorphism. Recombination traits were examined in pachytene chromosome spreads prepared from spermatocytes and oocytes. Synaptonemal complexes and mature recombination nodules were visualized with antibodies to SYCP3 and MLH1 proteins, correspondingly. Recombination rate was significantly higher (p = 0.0001) in barn swallow females (55.6 ± 6.3 recombination nodules per autosomal genome), caused by the higher number of nodules at the macrochromosomes, than in males (49.0 ± 4.5). They also showed more even distribution of recombination nodules along the macrochromosomes. At the same time, in the pale martin, sexual differences in recombination rate and distributions were rather small. We speculate that an elevated recombination rate in the female barn swallows might have evolved as a compensatory reaction to runaway sexual selection in males.

KW - Barn swallow

KW - Bird genome evolution

KW - Crossing over

KW - Heterochiasmy

KW - MLH1

KW - Pale martin

KW - Recombination

KW - Sand martin

KW - Sexual selection

KW - SYCP3

UR - http://www.scopus.com/inward/record.url?scp=85091676304&partnerID=8YFLogxK

U2 - 10.3390/genes11101119

DO - 10.3390/genes11101119

M3 - Article

C2 - 32987748

AN - SCOPUS:85091676304

VL - 11

SP - 1

EP - 11

JO - Genes

JF - Genes

SN - 2073-4425

IS - 10

M1 - 1119

ER -