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?
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.
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
Certainly! To understand how PsyDAG arrived at those numbers, let's break it down step by step.
In a diploid organism with 2n=8, the total number of chromosomes is 8.
Since the organism is diploid, it has two sets of chromosomes, one from each parent. Therefore, the organism has 2 copies of each chromosome.
Now, we want to calculate the probability that one of the organism's gametes (sex cells) will contain only paternally derived chromosomes, meaning no mixture of paternal and maternally derived chromosomes.
Out of the 8 chromosomes, there are 4 paternal chromosomes present.
To calculate the probability, we start with the first chromosome choice. There are 4 paternal chromosomes out of a total of 8, so the probability of choosing a paternal chromosome is 4/8.
Once a paternal chromosome is chosen, there are now 7 chromosomes left, out of which 3 are paternal. So the probability of choosing another paternal chromosome on the second selection is 3/7.
Now, we move on to the third selection. With 6 chromosomes remaining, 2 of them are paternal. So, the probability of choosing a paternal chromosome on the third selection is 2/6.
Finally, on the fourth selection, with 5 chromosomes left, only 1 of them is paternal. Thus, the probability is 1/5.
To find the overall probability of getting a gamete with only paternal chromosomes, we multiply the probabilities of each selection together:
(4/8) * (3/7) * (2/6) * (1/5) = ?
This gives us the final probability that one of the organism's gametes will contain only paternally derived chromosomes.