What I learned, Or what I thought I understood!

[eggsited chickens]

This is so confusing then! What can I believe. I reread the book last night and it definatly says the roo has 39 pair of chromosomes,but only one pair is a sex one. The hen on the other hand has 38 pairs of chromosomes and only one sex chromosome.

for those who have a different book, i found this in the chapter called " Managing Breeders" under the heading of "sex determination' which is chapter 8 in my book.

 

[nzpouter]

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where's the confusion...? 38 + 1(sex chr) = 39 pairs... 38 + 0 (remember hen only have 1 sex chr & pair means 2) = 38 pairs...

 

[eggsited chickens]

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Maybe I need another science lesson?

Ok, I see the pair of Roo is ZZ. But the hen part...they have ONE chromosome (at least the way I understand)...so how then can they have 1 z and 1 w? To me that is 2 chromosomes...not pairs but 2 individual chrom.

I'm sorry if I'm being dense...I was never good at biology/science...although it does intrigue me

But then the part I quoted earlier about the Hen only releasing a chromosome 50% of the time..."Every fertilized egg contains a sex chromosome from the cock, but a hen transmits her sex chromosome to only 50% of the eggs she lays. IF a fertilized egg contains chromosomes from both the cock and hen, it will hatch into a cockerel; if it contains only the single chromosome contributed by the cock, it will hatch into a pullet."

 

[OccamsTazer]

I'm not sure about whether the pullet has two sex chromosomes or just one, but it shouldn't really change anything.
ZW could just indicate Z=chromosome, W=blank. Remember though, that doesn't tell you anything about other traits, she still contributes half of all her other genetic material.