Next, we performed array comparative genomic hybridization aCGH on four families of zebrafish. Z Zool Syst Evol 3: 47— Expression of two genes associated with adult testis function were downregulated in wild-type ovaries compared with wild-type testes: amh 0. In mice, Nr0b1 is expressed in all tissues that constitute the hypothalamus-pituitary-gonad axis HPG.
Multifactorial selective breeding was carried out over a few generations for five lines of zebrafish to select for pairs that produced a sex-biased family. These studies therefore suggest that a polygenic system is regulating sex in domesticated lines, but that the particular genes involved vary between the independently selected lines.
Additionally, sperm cysts were smaller in mutants compared with wild-type.
A total of 5 lines were established and followed through two to four generations. Annu Rev Cell Dev Biol — From crosses that produced highly skewed sex ratio, usually three robust males and three robust females were chosen as brooders to produce the next generation.
Open in new tab. The fact that we were unable to obtain sex-linked markers from zebrafish with the same method provides an additional indication that no substantial differences exist between the male and female genomes. Negative results from both latter studies — together with the vast majority of cytogenetic data - suggest that zebrafish does not possess heteromorphic sex chromosomes.
Shift in the balance of pro-male and pro-female pathways will determine direction of gonad differentiation in zebrafish. Chromosome differentiation patterns during cichlid fish evolution. The ovaries of ddx5 -deficient females predominantly possessed stage I and II embryos, while various ovarian stages, from I to IV, were observed in wild-type females.
Another possibility is that the loss of the ddx5 gene causes oocyte arrest unrelated to the regulation of cAMP levels and oocyte arrest in the ddx5 -deficient mutant results in high cAMP concentration. Mapping of pigmentation QTL on an anchored genome assembly of the cichlid fish, Metriaclima zebra.
Waltham, MA: Academic Press; Genetic architecture of sex determination in fish: applications to sex ratio control in aquaculture. Mol Cell Endocrinol 35— We, therefore, propose that zebrafish sex determination is polygenic.