When sex determination in a species is predominantly genetic but environmentally reversible, exposure to (anthropogenic) changes in the environment can lead to shifts in a population's sex ratio. Such scenarios may be common in many fishes and amphibians, yet their ramifications remain largely unexplored. We used a simple model to study the (short-term) population consequences of environmental ...

The early bi-potential mammalian gonad requires the expression of a Y-linked gene, Sry, during a brief window of time to ensure proper testis development. WT1 and its direct target gene Sf1 function during sex determination as well as in the specified testes and ovaries. We have previously shown that the transcription co-factor CITED2 interacts with WT1 to stimulate the expression of Sf1 in the...

Rainbow trout (Oncorhynchus mykiss) females grow larger and mature later than males, making all-female stocks economically advantageous. The objective of this research was to develop methods for the production of monosex populations of trout through the use of sex steroids. The synthetic estrogen ethynylestradiol-17α (EE2) was administered in single period-immersion treatment of 400 µg/l for 1,...

Sex-role reversal, in which males care for offspring, can occur when mate competition is stronger between females than males. Secondary sex traits and mate attracting displays in sex-role-reversed species are usually more pronounced in females than in males. The red phalarope (Phalaropus fulicarius) is a textbook example of a sex-role-reversed species. It is generally agreed that males are resp...

Sex-typed reactions are contrasted in male and female normals and chronic schizophrenics. In general, the schizophrenics show sex-role alienation on tests which contain a self-image reference (a Role Playing Test, a Body Parts Acceptance Test, and a Figure Preference Test), Female schizophrenics tend to react in a more assertive manner like normal males, and male schizophrenics in a more sensit...

After two generations of backcrossing six different Y-consomic strains onto a C57BL/6J inbred mouse strain with a dominant hemimelia (Dh) mutation, a small percentage of Dh/+ males containing a Y chromosome from the AKR/J or RF/J strain showed hermaphrodism; they lacked the right testis and had an ovary and a uterus instead. Approximately 15% of Dh/+ females considered to be phenotypically norm...