| MadSci Network: Genetics |
Can you have a yy genotype and produce a person out of it?
No, it is impossible to produce a viable human that is lacking an X chromosome, as in a yy individual. There are several genes on the X chromosome that cause disease when deleted, such as the genes for Haemophilia, Menkes syndrome, familial Leukodystrophy, and several others genes that are homozygous lethal, i.e. at least one copy is required for the person to survive. An embryo without any X chromosomes would not have any copies of any of these genes, and would die early in development.
There are individuals with three of sex-chromosomes: XXY (Klinefelter's Syndrome) individuals are male with abherent female characteristics and are ususally sterile; XYY are male and may show increased aggression; and XXX (triple X syndrome) are female and may show slight retardation (even though the scientific results are inconclusive, the XYY and XXX syndromes have been the subjects of much political debate by people trying to prove that all men are killers and all women are stupid). There are also individuals with only one sex-chromosome: X0 (Turner's syndrome) individuals are female with various minor developmental defects and are usually sterile; Y0, like YY, is inviable.