Posted by Axel on .
My original question: In a diploid organism with 2n=8, what is the probability that one of its gametes will contain only paternally derived chromosomes (ie, not a mixture of paternal and maternally derived chromosomes)?
PsyDAG replied: Since 4 of the 8 are paternal,
4/8 * 3/7 * 2/6 * 1/5 = ?
My question: can you explain how he/she got these numbers?

Science 
PsyDAG,
I assume that, if 2n = 8, there are 4 paternal and 4 maternal chromosomes.
The first paternal chromosome will be 4/8, and without replacement, the second will be 3/7, the third, 2/6 and the fourth, 1/5.
The second is 3/7, because only 3 paternal chromosomes are left of the remaining 7.
The progression continues.
I hope this helps you understand the process. 
Science 
Axel,
Thank you very much, I don't remember learning it like this but this certainly does help alot and this makes it easier to understand. Once again, thank you