Q. Down's syndrome is caused by an extra copy of chromosome number . What percentage of offspring produced by an affected mother and a normal father would be affected by this disorder ?

 1424  173 AIPMTAIPMT 2003Principles of Inheritance and Variation Report Error

Solution:

Down's syndrome is the example of autosomal aneuploidy. Here, an extra copy of chromosome 21 occurs. As it is an autosomal disease, the offsprings produced from affected mother and normal father should be 50%.