What are polygenes? Explain with suitable example.

Answer:  Polygenes: Characters are determined by two or more gene pairs, and they have additive or cumulative effect. Such genes are called cumulative genes or polygenes or multiple factors. Example Human skin colour: i. Population derived from marriage between negro and white […]

Distinguish between: Phenotype and Genotype.

Phenotype and Genotype Phenotype Genotype 1.  It is the physical appearance of an organism. It is the physical appearance of an organism. 2.  It can be directly seen. It is determined by inheritance pattern. 3. Phenotype can be determined from […]

Distinguish between: Dominant and Recessive character.

Dominant and Recessive character Dominant character Recessive character  1.  The characters that are expressed in F1 generation are dominant. The characters that are not expressed in F1 generation are recessive. 2.  It is expressed in presence of dominant as well […]

Distinguish between: Homozygous and Heterozygous.

Homozygous and Hererozygous. Homozygous Heterozygous  1. Organisms having  identical alleles for a character are homozygous.  Organisms having dissimilar alleles for a character are heterozygous. 2.  It is pure or true breeding  It is hybrid  3.  They form only one type […]

State Mendel’s first law of inheritance or law of dominance.

The First Law of Inheritance  Law of dominance states that “in a cross between two homozygous organisms differing in a single pair of contrasting character, the character which is expressed in the F1 generation is called dominant character and the character which […]

What are the reasons for Mendel’s success?

Answer The reasons for Mendel’s success are: i. Mendel chose garden pea plant for his experiments which was an annual, naturally self-pollinating plant with several pairs of contrasting characters. ii. Mendel concentrated only on one character at a time. iii. He […]

What is Punnett square/Checker Board?

Answer  Punnett square is a graphical representation to calculate the probability of all possible genotypes and phenotypes of offsprings in a genetic cross. It was developed by Reginald C. Punnett.