No, all chimeras are not female. Chimeras can be male or female, or even have a mix of both male and female cells.
Understanding Chimerism and Sex Determination
A chimera is an organism composed of cells with distinct genotypes, meaning they originate from different individuals or zygotes. This mixture can occur naturally or be artificially induced. Sex determination, whether an organism develops as male or female, is determined by its genetic makeup. In mammals, this is primarily dictated by the presence or absence of the Y chromosome.
Sex Discordant Chimeras
The reference states that "Even sex-discordant chimeras can have a normal male or female phenotype." This clearly indicates that chimeras are not exclusively female. Sex-discordant chimeras have a mix of XX (female) and XY (male) cells. The referenced information also indicates that the phenotype (observable characteristics) does not always align perfectly with the mixture of sex chromosomes, noting that out of 50 individuals with 46,XX/46,XY karyotype, only 28 displayed ambiguous genitalia or true hermaphroditism. This means that some chimeras with both XX and XY cells can still develop as phenotypically male or female.
Examples of Chimera Sex
- Male Chimera: An individual could be a chimera with a majority of XY cells, leading to the development of male characteristics.
- Female Chimera: Conversely, a chimera with primarily XX cells may develop as female.
- Intersex Chimera: Some chimeras may have a more even mix of XX and XY cells, potentially leading to intersex conditions, as suggested by the reference's mention of "true hermaphrodites" and "ambiguous genitalia."
