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The Mozambique tilapia ( Oreochromis mossambicus ) is a fascinating taxon for evolutionary and ecological research. It is an important food fish and one of the most widely distributed tilapias. Because males grow faster than females, genetically male tilapia are preferred in aquaculture. However, studies of sex determination and sex control in O . mossambicus have been hindered by the limited characterization of the genome. To address this gap, we assembled a high-quality genome of O . mossambicus , using a combination of high coverage of Illumina and Nanopore reads, coupled with Hi-C and RNA-Seq data. Our genome assembly spans 1,007 Mb with a scaffold N50 of 11.38 Mb. We successfully anchored and oriented 98.6% of the genome on 22 linkage groups (LGs). Based on re-sequencing data for male and female fishes from three families, O . mossambicus segregates both an XY system on LG14 and a ZW system on LG3. The sex-patterned SNPs shared by two XY families narrowed the sex determining regions to ∼3 Mb on LG14. The shared sex-patterned SNPs included two deleterious missense mutations in ahnak and rhbdd1 , indicating the possible roles of these two genes in sex determination. This annotated chromosome-level genome assembly and identification of sex determining regions represents a valuable resource to help understand the evolution of genetic sex determination in tilapias.
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What controls sex development in fish?
In mammals and in birds, the sex of an individual is determined by its genes. A sex determining gene on a sex chromosome influence the development of ovaries or testes. But sex in fishes is much more diverse! What controls sex development in fish? Sex genes like in mammals and birds? Or do other types of sex determination systems exist in fish? In this short scientific graphic novel, Sophia Breslin, John Postlethwait, and Thomas Desvignes introduce you to the control of sex determination in fish: from the genetic regulation by sex determining genes and sex chromosomes to various cases of hermaphrodism and the influence of the environment, revealing the myriad of different sex determination systems found in fishes.
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- Award ID(s):
- 2232891
- PAR ID:
- 10615167
- Publisher / Repository:
- scholarsbank
- Date Published:
- Subject(s) / Keyword(s):
- gonad development sex determination fish ovary testis
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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