Question

If a character is controlled by 8 alleles of a gene calculate the possible genotypes in the population.
A. 35
B. 36
C. 18
D. 37

Answer 1

Alleles are alternative forms of gene, that occupy the same location on homologous chromosomes (that is, two chromosomes carrying similar alleles for a particular character). They play a very important role in genetic coding of any individual.

Complete answer:
Every trait or character in an organism has some specific genetic coding that maintains individuality of an organism. This genetic information is encrypted in the form of genes that design certain traits or characters in the individual. These characters are either recessive or dominant in behaviour, depending upon the nature of the alleles of that particular character. Genotype can be defined as the genetic coding or genetic combination for any trait in any individual. It is specific for every character. All the characters that are genetically controlled have a particular genotype. However, there can be many possible genotype combinations for a single trait out of which only the dominant trait is observable.
Genotypes for any allele can be calculated with the help of formula n(n+1)/2. Here, n is the no of alleles. As given in the question, the value of 'n' that is the number of alleles is 8. By substituting the values in the formula, the number of genotypes come out to be 36.

Therefore, 8 alleles of a gene can have 36 possible genotypes in the population. Therefore, option B is the correct answer.

Note:
Genes are the actual code carriers of any trait in any individual. Alternative genes are referred to as alleles. They have specific positions on chromosomes which helps in transmission of alleles or genetic information from one generation to another.