Integrated mRNA and miRNA expression profile analysis of female and male gonads in Hyriopsis cumingii

Hyriopsis cumingii is an important species for freshwater pearl cultivation in China. In terms of pearl production, males have larger pearls and better glossiness than females, but there are few reports focusing on the sex of H. cumingii. In this study, six mRNA and six microRNA (miRNA) libraries were prepared from ovaries and testes. Additionally, 28,502 differentially expressed genes (DEGs) and 32 differentially expressed miRNAs (DEMs) were identified. Compared with testis, 14,360 mRNAs and 20 miRNAs were up-regulated in ovary, 14,142 mRNAs and 12 miRNAs were down-regulated. In DEGs, the known genes related to sex determinism and/or differentiation were also identified, such as DMRT1, SOX9, SF1 for males, FOXL2 for females, and other potentially significant candidate genes. Three sex-related pathways have also been identified, which are Wnt, Notch, and TGF-beta. In 32 DEMs, the three miRNAs (miR-9-5p, miR-92, miR-184) were paid more attention, they predicted 28 target genes, which may also be candidates for sex-related miRNAs and genes. Differential miRNAs target genes analysis reveals the pathway associated with oocyte meiosis and spermatogenesis. Overall, the findings of the study provide significant insights to enhance our understanding of sex differentiation and/or sex determination mechanisms for H. cumingii.

Protostrongylus rufescens: a cytogenetic study

ABSTRACTThe diploid chromosome number of Protostrongylus rufescens is 2n=11 for males and 2n=12 for females. So, the sex determinism mechanism is XO/XX. The study of the genetic behaviour of this species has been made. In diakinesis stage the bivalents show typical tetrads with cross, Ø, and lineal configurations. The division of the sexual chromosome is prereductional for the first meiotic division.