Lecture 8 - Aneulploidy And Non-disjunction Flashcards
How could meiosis go wrong - what would happen is chromosomes didn’t recombine?
They would not be attached and therefore behave independently of one another. This means there would be 50% chance of them going to the same pole
How could meiosis go wrong - what would happen is crossing over happened to close to the telomere?
There’s not as much cohesin and therefore easier to lose which would cause sliding
What would happen is cohesin isn’t protected at the centromeres?
Sister chromatids separate and can go to either pole. If they go to the same one this is bad
What does missegregation of chromosomes cause?
Aneulploidy
What is disomy
2 homologous chromosomes
What is trisomy?
3 homologous chromosomes
What is monosomy?
1 chromosome
What type of aneuploidy is trisomy 21?
Down syndrome
What happens if you have trisomy 13 or trisomy 18?
Can survive birth but die shorty after
What happens in turner syndrome? (X)
Spontaneous abortions or females will have reduced height and be infertile
What happens in Klinefelter syndrome (XXY)?
Male increased height and infertile
Why is aneuploidy bad?
There is a 50% increase or decrease in gene dosage. Most genes have no defects but some are harmful which means if they are increased or decreases this could be very bad and cause death
Do small chromosomes deal with aneuploidy better?
Yes because there is less genes
Is aneuploidy in oocytes higher in humans than other mammals?
Yes
Where do aneuploidy come from?
Either mother or father or from meiosis 1 or meiosis 2