Schilders disease is a progressive degeneration of the central nervous system that leads to death by age 2. The disease is caused by a simple autosomal recessive mutation. A couple loses its first two children to Schilders disease. If they decide to have a third child, what is the probability that it will have the disease

The probability will be 25% (1/4)

Explanation:

Schilder's syndrome is a degenerative and progressive lethal disease caused by the demyelination of nerve cells in the brain and spinal cord. Since it is a lethal recessive autosomal disease, both the father and the mother have a single copy of the mutant allele, thereby the probability of obtaining a lethal combination will be:

SN X SN >>

1/2 x 1/2 = 1/4 = 25%

where N and S are normal and lethal alleles, respectivelyvely

name and explain one of the event that occurs during meiosis that increases the variation in offspring even more than simple reproduction?

the answer is cell division : )