Question

A genetic disorder is controlled by several genes. The effects of the alleles at these loci are additive. Assume that there is no environmental effect. For each locus, a capital letter in the genotype confers 4 units of risk. Each lower case letter confers 2 units of risk. Individuals with more than 25 risk units have the disorder.

Joseph has genotype Ee HH Nn Rr. Does Joseph have the disorder? AnswerYes/No

Janet has the genotype ee HH Nn rr. Does Janet have the disorder? AnswerYes/No

Joseph and Janet are the parents of a child. What is the maximum number of risk factors that could be present in this child? Give your answer in numerical form. Answer

Answer 1

Joseph :

Capital letter confers 4 units of risk and Joseph has 5 capital letter genes = 5*4 = 20

Each small letter confers 2 units of risk and Joseph has 3 small letter genes = 3*2 = 6

In total Joseph has risk factor of 26 and more than 25 units of risk person or individual has disorder.

Hence yes, Joseph has disorder

Jannet :

Jannet has 3 capital letters and 5 small leters genes

=( 3*4)+ (5*2) = 22

No, jannet does not have disease

Maximum number of risk units which can be found in the child will have genotype of

EeHHNNRr =has 6 capital letters and 2 small leters

= 6*4 = 24 and 2*2 = 4

24+4 = 28