Journal
GENOME BIOLOGY
Volume 22, Issue 1, Pages -Publisher
BMC
DOI: 10.1186/s13059-021-02430-y
Keywords
Heterochromatin; Centromere; Sex chromosome; Fish genome; Recombination suppression
Funding
- Special Fund for Agro-Scientific Research in the Public Interest of Fujian Province of China [2020R1014002]
- Fujian Provincial Marine and Fishery Structure Adjustment Fund [2020MDS-YT005]
- National Natural Science Foundation of China [32002360]
- Natural Science Foundation of Yunnan Province of China [2018FB048]
- scientific research innovation program Xiyuanjiang River Scholarship from the College of Life Sciences, Fujian Normal University
- Erwin Schrodinger Fellowship from the Austrian Science Fund (FWF) [J4477-B]
- Austrian Science Fund (FWF) [J4477] Funding Source: Austrian Science Fund (FWF)
Ask authors/readers for more resources
The study on the haplotype-resolved genome assembly of zig-zag eel sheds light on the evolution of sex chromosomes and recombination suppression mechanisms, revealing a similar sex-linked region on the X and Y chromosomes and identifying a potential sex-determining gene in the SLR.
Background: The origin of sex chromosomes requires the establishment of recombination suppression between the proto-sex chromosomes. In many fish species, the sex chromosome pair is homomorphic with a recent origin, providing species for studying how and why recombination suppression evolved in the initial stages of sex chromosome differentiation, but this requires accurate sequence assembly of the X and Y (or Z and W) chromosomes, which may be difficult if they are recently diverged. Results: Here we produce a haplotype-resolved genome assembly of zig-zag eel (Mastacembelus armatus), an aquaculture fish, at the chromosomal scale. The diploid assembly is nearly gap-free, and in most chromosomes, we resolve the centromeric and subtelomeric heterochromatic sequences. In particular, the Y chromosome, including its highly repetitive short arm, has zero gaps. Using resequencing data, we identify a similar to 7 Mb fully sex-linked region (SLR), spanning the sex chromosome centromere and almost entirely embedded in the pericentromeric heterochromatin. The SLRs on the X and Y chromosomes are almost identical in sequence and gene content, but both are repetitive and heterochromatic, consistent with zero or low recombination. We further identify an HMG-domain containing gene HMGN6 in the SLR as a candidate sex-determining gene that is expressed at the onset of testis development. Conclusions: Our study supports the idea that preexisting regions of low recombination, such as pericentromeric regions, can give rise to SLR in the absence of structural variations between the proto-sex chromosomes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available