RT Journal Article
SR Electronic
T1 Single-Cell Transcriptomics reveals relaxed evolutionary constraint of spermatogenesis in two passerine birds as compared to mammals
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.01.22.477241
DO 10.1101/2022.01.22.477241
A1 J. Carolina Segami
A1 Marie Semon
A1 Catarina Cunha
A1 Claudia Bergin
A1 Carina F Mugal
A1 Anna Qvarnström
YR 2022
UL http://biorxiv.org/content/early/2022/01/23/2022.01.22.477241.abstract
AB Spermatogenesis is a complex process where spermatogonia develop into haploid, mobile sperm cells. The genes guiding this process are subject to an evolutionary trade-off between preserving basic functions of sperm while acquiring new traits ensuring advantages in competition over fertilization of female gametes. In species with XY sex chromosomes, the outcome of this trade-off is found to vary across the stages of spermatogenesis but remains unexplored for species with ZW sex chromosomes. Here we characterize avian spermatogenesis at single cell resolution from testis of collared and pied flycatchers. We find evidence for relaxed evolutionary constraint of genes expressed in spermatocyte cells going through meiosis. An overrepresentation of Z-linked differentially expressed genes between the two species at this stage suggests that this relaxed constraint is associated with the lack of sex-chromosome silencing during meiosis. We conclude that the high throughput of bird spermatogenesis, at least partly, is explained by relaxed developmental constraint.Competing Interest StatementThe authors have declared no competing interest.