28. What is the probability of having 2 out of 3 albino children if the parents
ID: 99378 • Letter: 2
Question
28. What is the probability of having 2 out of 3 albino children if the parents are both carriers for this recessive trait?
(a) 1/3 (b) 1/4 (c) 3/4 (d) 3/64 (e)9/64
key 28 is e
Please give a good explanation to your answer, will give a thumbs up, thank you. (visual learner)
26. With the following genes d & t. The following cross DT/dt x dt/dt produces 20 flies with the genotype Dt/dt out of a total of 200 progeny. This suggests: (a) The two genes may be located on different chromosomes. (b) The 2 genes are on the same chromosome but are very far apart (c) The 2 genes are 20 centimorgans apart (d) The 2 genes are 40 centimorgans apart (e) The 2 genes are over 50 centimorgans apartExplanation / Answer
Answer 26: According to the information, it must be carefully noted that the genotype of the test fly (the progeny in this case) is same to one of the parents.This means that there are very few parental class type progeny in this population of flies suggesting that the genes are located very far away from each other. The remote localization of these genes is an indicative of high probability of crossing over thus resulting in a very few offsprings of parental type. This can be possible only if the genes are located very close to each other i.e. nearly 10 or 20 cM apart. Thus choice C is correct.
Answer 28: According to the information, both parents carry the recessive trait albino trait (no pigmentation) gene. If both parents are normal, it means they are heterozygous for the allele. Let us assume that there genotypes are given by Aa and Aa both. Thus, the Punnett square can be formulated as:
Thus, the genotypes will be: AA: Aa::aa :: 1:2:1
Phenotype: Normal : Albino :: 3:1
Thus, the probability of having one child albino is: 1/4
The probability of having three childs albino will be: 1/4 * 1/4 *1/4 or 1/64
Thus, none of the choices is correct. This is because the probability of a child having or not having a trait is independent of another child's probabilities.
A a A AA Aa a aA aaRelated Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.