Answer:
6,25%
Explanation:
Considering that the couple has a trait of sickle cell anemia, we know that both are heterozygous for the disease (Aa) and therefore can have children with the following genotypes:
Parents: Aa X Aa
Children: AA(A x A), Aa(A x a), Aa (a x A) and aa(a x a)
Knowing that sickle cell anemia only occurs in homozygous individuals, the probability for children to have the disease according to each crossing is:
A x A = 1/4 = 25%
A x a = 1/4 = 25%
a x A = 1/4 = 25%
a x a = 1/4 = 25%
The probability of forming each homozygous child (aa) is 1/4 or 25%. Since they are two children, the probability of both having sickle cell anemia is calculated by multiplying the probability of each, so:
1/4 × 1/4 = 1/16 = 0.0625 = 6.25%
It is concluded that the probability of a heterozygous couple for sickle cell anemia to have two children with the disease is 6.25%.
Http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0072434/
There is a website with some info. Hope it helps! :)
Mitosis is a type of cell division which results in two daughter cells which have the same number and kind of cells as the parent nucleus. Mitosis is used to replace worn out cells and for growth. In plants, a new cell was is built between the daughter cells, while in animals the cell membranes constrict and pinch the parent cell into daughter cells.
