crossing over

[laura22]

Can anyone comment on 'crossing over' re formation of sex cells? With regard to pedigrees and female families etc


Thanks, L.

[xfactor fan]

Well in terms of the YX, and XX chromosomes, there is little or no crossover with the YX pair. There just isn't all that much of the Y chromosome.

So crossovers happens in the female, in the XX pair.

Is that what you wanted to know?

[laura22]

Yes, ok. Thanks

L.

[Pan Zareta]

Can anyone comment on 'crossing over' re formation of sex cells? With regard to pedigrees and female families etc


Thanks, L.

Female families are defined by mitochondrial DNA (mtDNA), not a sex cell or sex chromosome. The mitochondria are in the cytoplasm of the cell, not in the nucleus with the sex chromosomes and 'non-sex chromosomes' (autosomes). By the time of fertilization the sperm's mitochondria have been eliminated, so there is no crossing over (recombination) and the embryo receives only unchanged maternal mtDNA. Analysis of mtDNA is useful for identifying errors in the stud book record.

[laura22]

Thanks Pan, most helpful

L.