Could someone explain what the y and x chromosome are, what part they play in our biology and how they determine our sex? I hear this topic come up a lot and I have no idea what they are. Doesn’t an extra chromosome also mean a person might have down syndrome? Thanks guys.
(Not looking for a political debate btw, just straight biology, thank you)
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Others have answered the first part, but I just wanna address this
>Doesn’t an extra chromosome also mean a person might have down syndrome?
Down syndrome isn’t just an extra chromosome, it’s specifically an extra copy of chromosome 21. It’s also called trisomy 21, since that person will have 3 copies of chromosome 21 instead of the normal 2 copies.
The only other syndromes you can see with extra chromosomes are trisomy 13 (Patau syndrome) and trisomy 18 (Edward’s syndrome). These two are much more severe than down syndrome and most babies won’t live beyond a few days or weeks.
No other trisomies are seen (except with the sex chromosomes) because they aren’t compatible with life, and an embryo who has one will most likely result in a miscarriage.
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