Schistosomiasis is a major parasitic disease that seriously affects human health, and the schizoite family to which the pathogen Schistosomiasis belongs is the only hermaphrodite taxa in the phylum Oblates. Although schistosomiasis is sex-determined by ZW type, the isolation and establishment of sex chromosomes does not give females the full ability to independently complete sexual development and sexual maturation. In the process of developing from child to adult, schistosomiasis has a unique phenomenon of hermaphroditism. Only under the continuous stimulation of the male can the female mature and continue to lay eggs. Eggs are the main causative factor of schistosomiasis and the main stage of schistosomiasis transmission. Therefore, sex determination and differentiation are key links in the development and pathogenesis of schistosomiasis. However, due to the lack of high-quality chromosomal-level genomic data, the isolation and identification of Schistosomiasis Japanese sex chromosomes has become a major problem, so that the evolutionary law of its sex chromosomes and the genetic basis of sex determination and differentiation are still unclear.
On July 17, 2022, Xu Xindong, et al. of tongji University School of Medicine published online an article titled Chromosome-level genome assembly defines female-biased genes associated with sex determination and differentiation in the Human blood fluke Schistosoma japonicum's research treatise. The paper identified the ZW sex chromosome by assembling a high-quality chromosomal-level whole genome of Schistosomiasis S. and revealed the evolutionary patterns of the Schistosomiasis Japanese sex chromosomes and the genes associated with sex determination and differentiation of females.
The study comprehensively used Illumina ii generation sequencing data, PacBio single molecule long reading segment sequencing data, 10× Genomics reading data and Hi-C sequencing data, and used the de novo assembly (denovo) strategy to obtain the chromosomal level of the Japanese schistosomiasis genome. The obtained genome is 406.6Mb long and includes 7 autosomes, one Z chromosome and one W chromosome fragment. By comparing the "evolutionary faults" of the Schistosoma s. and Schistosoma mansonii sex chromosomes, it was found that the two shared an ancient recombinant inhibition event, and three other recombinant inhibition events occurred only in Schistosomiasis Japan. Thirty-five W-linked genes, including 3 transcription factors and 1 chromatin regulatory protein, were annotated on the W sequence, which are candidate genes for sex determination in schistosomiasis females. In female worms, 257 female high-expression genes were also identified, and it is interesting that most of these genes are located on autosomal or Z chromosomes in the form of gene clusters, such as the 4 eggshell protein genes that are closely related to the formation of eggs are located on chromosome 2 in a head-to-tail connection manner. In addition, it was found that the conserved regulatory elements shared by genes within the cluster were conducive to the coordinated high expression of eggshell proteins during spawning.
Sequencing and assembly strategies for the chromosomal-level genome of Schistosomiasis Japan
The study not only reveals the evolutionary historical events of the Japanese schistosomiasis sex chromosome, but also the newly identified sex-linked genes are of great significance for the future by inhibiting female eggs to intervene in schistosomiasis pathogenesis and block the spread of diseases.
Associate Professor Xu Xindong of Tongji University School of Medicine and Dr. Yifeng Wang of zhejiang University Institute of Life Sciences are the co-first authors of this paper; Professor Zhang Qingfeng of Tongji University School of Medicine, Professor Zhou Qi of Zhejiang University, Professor Cao Jun of Jiangsu Institute of Schistosomiasis Prevention and Control, and Professor Donald P. McManus of Queensland Medical Research Institute of Australia are the co-corresponding authors of this article.
Thesis Link:
https://doi.org/10.1111/1755-0998.13689
Model Maker: Eleven
Reprint Notice
【Original Article】BioArtMED original article, welcome to personal forwarding and sharing, without permission is prohibited from reprinting, the copyright of all published works is owned by BioArtMED. BioArtMED reserves all statutory rights and will be held accountable for violation.