Question

(6 pts.) 2. Please briefly describe the causes of both Down syndrome and auses of both Downsyndrome and familial Down syndrome at the chromosomal level (abnormal numbers or abnormal arrang normal numbers or abnormal arrangement) respectively. a) Down Syndrome b) Familial Down syndrome (8 3. Mary has widows peak hairline and AB type blood (Ww!^B) and her husband Tom has straight hairline and AB type blood. a) What is the genotype of Tom? W b) What is the probability that their son Leo has A type blood and straight hairline? (Use a fou diagram to support your answer.

Answer 1

Ans- down syndrome show trisomy 21chromosome.

Ansa Et cause by genetic disorder (a) Bown's syndrome: It cause by genet Is the presence of an additional copy of ne chromosome number al (trisomy 210. The affected individual is short statue with small round head, terrowed tongue and partially open mouth. Psychomotor and mental development is retarded. (b) Familial Down's syndrome : Itis Cause of the inheritance of a chromosome with the long arm of chromosome al translocated onto chromosome 14. There is no phenotype associated with the trans located itself.

Familial down syndrome show long arm of chromosome 21 translocated onto chromosome 14.