Cherax quadricarinatus exhibit sexual dimorphism, with males outpacing females in size specification and growth rate. However, there is limited understanding of the molecular mechanisms underlying sex determination and sex differentiation in crustaceans. To study the differences between intersex individuals and normal individuals, this study counted the proportion of intersex individuals in the natural population, collected the proportion of 7 different phenotypes in 200 intersex individuals, and observed the differences in tissue sections. RNA-seq was used to study the different changes in the transcriptome of normal and intersex gonads. The results showed that: the percentage of intersex in the natural population was 1.5 %, and the percentage of different types of intersex ranged from 0.5 % to 22.5 %; the sections revealed that the development of normal ovaries was stagnant at the primary oocyte stage when intersex individuals with ovaries were present; We screened for pathways and genes that may be associated with gonadal development and sex, including ovarian steroid synthesis, estrogen signaling pathway, oocyte meiosis, progesterone-mediated oocyte maturation, etc. Relevant genes including tra2a, dmrta2, ccnb2, foxl2, and smad4. This study provides an important molecular basis for sex determination, sex-controlled breeding, and unisex breeding in red crayfish.

红螯螯虾表现出性别二态性，雄性在体型规格和生长速度方面均超过雌性。然而，人们对甲壳类动物性别决定和性别分化的分子机制了解有限。为了研究双性个体与正常个体的差异，本研究统计了自然群体中双性个体的比例，收集了200名双性个体中7种不同表型的比例，并观察组织切片的差异。RNA-seq 用于研究正常和双性性腺转录组的不同变化。结果显示：自然人口中双性人的比例为1.5%，不同类型双性人的比例在0.5%至22.5%之间；切片显示，当存在具有卵巢的双性个体时，正常卵巢的发育在初级卵母细胞阶段停滞不前；我们筛选了可能与性腺发育和性别相关的通路和基因，包括卵巢类固醇合成、雌激素信号通路、卵母细胞减数分裂、孕激素介导的卵母细胞成熟等。相关基因包括tra2a、 dmrta2、 ccnb2、 foxl2和smad4。该研究为红螯虾的性别决定、性别控制育种和雌雄育种提供了重要的分子基础。