down syndrome - kaur

[ArchivalUser]

plzz any body tell me where nondisjunction occur in this i mean in meiosis 1 or 2 .
thanks in advance gl

[ArchivalUser]

come on any body

[ArchivalUser]

nondisjunction can occur at either - meiosis1 or2.

[ArchivalUser]

Yes, it can occur at either meiosis I or II. The Q stem will have to give you some clue to distinguish the two.

For example, father is AB, mother is CD, then if kid is ABC, it is nondisjunction of father's at meiosis I (since normally he is supposed to give either A or B to the kid, not both)

If from father's meiosis II, the kid will be AAC, or BBC, or AAD, or BBD, since father's A or B gene got through normal meiosis I, but experience nondisjunction at Meiosis II.

That's what I understood. Hope it helps.

[ArchivalUser]

hi Danille

so its not specific in down syndrome it can occur either in meiosis 1 or 2 ?

[ArchivalUser]

Yes, Kaur, I think nondisjunction is not unique to Down syndrome. It is the most common cause of all trisomies, right? Yes, nondisjunction can occur either in meiosis I or II.

[ArchivalUser]

thanks gl danille.