Question

Answer in 200 to 250 words:
a) What are multiple alleles? Give an example.
b) Write the symptoms of Klinefelter's syndrome.

Answer 1

a) When more than two alleles control the single trait are known as multiple alleles. Multiple allelism refers to the presence of more than two contrasting alleles for a gene. Human blood group inheritance is the governed by three alleles namely I${}^A$, I${}^B$ and i. Alleles I${}^A$ and I${}^B$ show codominance as I${}^A$ I${}^B$ genotype produce AB blood group that exhibits characters of both I${}^A$ and I${}^B$ alleles. Allele 'i' is recessive to both I${}^A$ and I${}^B$; I${}^A$ i and I${}^B$ i phenotypes exhibit A and B blood groups respectively.

b) Klinefelter's syndrome is the condition in which the male have one extra copy of the X-chromosome. The symptoms associated with this disorder are:

• Delay in speech.
  
• Enlarged breast tissues.
• Small testes and short penis.
• Low sperm count.
• Tall stature.
• Delayed puberty.