Question

Assignment #10 Chapters 11 & 12

1. The mother of a child who was just diagnosed with type 1 diabetes turns to the child’s father and says, “This is all your fault. Your father has type 2 diabetes.” Is she correct in her assumption that the child inherited diabetes from his father’s family? Explain your response

2. Why sickle cell disease/trait and cystic fibrosis are considered probable genetic evolutionary disorders?

3. Why is carrier status for Duchenne muscular dystrophy (DMD) usually not transmitted from affected fathers to daughters, even though this disorder has an X-linked transmission pattern

4. Why is there such a high rate of spontaneous mutation among the genes responsible for classic hemophilia, Duchenne muscular dystrophy, and achondroplasia? 5. Edward has diabetes mellitus type 2 (DM type 2).He is struggling to maintain his blood sugar within normal limits. Edward also suffers from obesity and has been unable to control his weight with diet and exercise. He asks you if his problem is due to genetics. He points out that his mother also had type 2 diabetes and was obese. He also asks why his identical twin brother, Edgar, does not have diabetes even though they share genes and grew up in the same environment.

A. What would you tell Edward about the genetics of DM type 2?

B. What will you tell Edward about the relationship between DM type 2 and obesity? What will you tell Edward about the relationship between DM type 2 and obesity?

C. What do you think about genetic testing for DM type 2 in young? Is this likely to be successful at identifying a genetic cause?

D. Would genetic counseling benefit Edward and his family?

Answer 1

1)

Yes, she is correct. The disorders have many similarities, the genetic contribution to the two types of diabetes are vey similar. There is an increase riskfor type 1 diabetes among the offspring of those who have type 2 diabetes.

2)

Sickel cell and cystic fibrosis both are autosomal recessive disorder. They affect less number of people but found in large population in the recessive form. Because of natural selection different alleles confer the advantage of survival in the different environment. Cycles of the prevalence infectious disease and virulence sometimes reflect natural selection.

In case of sickle cell, the advantage is that it prevent body from malaria infection. In cystic fibrosis the anatomical defect that underline CF protects against the diarrheal illenesses. This is the reason that natural selection will prefer these alleles and these diseases considered as the probable genetic evolutionary disorder.