3 ms·
Consider that in all males, all of the X chromosome genes are expressed. What's more, with X inactivation, one of the chromosomes in XX becomes almost complete
by shagie 4y ago
Consider that in all males, all of the X chromosome genes are expressed.
What's more, with X inactivation, one of the chromosomes in XX becomes almost completely inactive and all of the genes on the other chromosome are expressed.
https://en.wikipedia.org/wiki/X-inactivation https://en.wikipedia.org/wiki/X-inactivation
> X-inactivation (also called Lyonization, after English geneticist Mary Lyon) is a process by which one of the copies of the X chromosome is inactivated in therian female mammals. The inactive X chromosome is silenced by being packaged into a transcriptionally inactive structure called heterochromatin. As nearly all female mammals have two X chromosomes, X-inactivation prevents them from having twice as many X chromosome gene products as males, who only possess a single copy of the X chromosome (see dosage compensation).
- thaumasiotes 4y ago> What's more, with X inactivation, one of the chromosomes in XX becomes almost completely inactive There is a huge distance between "almost completely inactive" and "inactive". A Turner's syndrome patient (only one X chromosome) usually has several obvious physical defects, including sterility. Interestingly, as far as I'm aware the things we usually think of as "X-linked" (more common in men, inherited as a recessive phenotype on the X chromosome - things like red/green colorblindness and male-pattern baldness) aren't as common in Turner's patients as you might expect.