Question

A meiosis occurs in which a resulting egg contains 14 chromosomes from the father and 9 chromosomes from the mother. How many possible chromosomal combinations could lead to this outcome?

What is the probability that any given egg will contain 14 chromosomes from the father and 9 chromosomes from the mother?

Answer 1

A meiosis division results in 2 daughter cells containing half the genetic material of the original mother cell. It is generally carried out for gamete and sex cell formation.
Keeping that in mind we can easily see that the parent cell had 23 pairs of chromosomes (i.e. 14 + 9 = 23), out of which the daughter cell happened t receive 14 from the father and 9 from the mother.
Using simple combinatorial analysis we can see that we need to choose any 14 chromosomes from the list of 23 and the remaining choice of 9 chromosomes will automatically be assigned to the mother. Hence ²³C₁₄ denotes the number of possible chromosomal combinations that can lead to this, when calculating from the father's perspective. We will arrive onto the same answer when taking into account the mother's perspective, wherein we will come to the final number of ²³C9
ANSWER Possible chromosomal combinations could lead to this outcome = ²³C₁₄= ²³C₉

For any one choice of parent of chromosome we have 2 outcomes (father or mother), so for 23 pairs we have 2²³ outcomes. Hence probability of finding given egg
= (Number of favourable cases/Total cases)
= (²³C₁₄/ 2²³) ANSWER