Describe one gene inheritance.

Explanation

The study of inheritance of a single pair of alleles or factors of a trait at a time (monohybrid cross) is called one gene inheritance.
= Based on his observations on monohybrid crosses, Mendel proposed two general rules in order to consolidate his understanding of inheritance in monohybrid crosses.
= These rules are called the principles or laws of inheritance.
= They are :
= Law of Dominance (First Law) : (i) Characters are controlled by discrete units called factor. (ii) Factors occur in pairs. (iii) In a dissimilar pair of factors, one member of the pair is dominant while the other is recessive.
= This law is used to explain the expression of only one of the parental characters in a monohybrid cross in the `F_1` generation and the expression of both in the `F_2` generation. It also explains the proportion of 3 : 1 ratio obtained in the `F_2` generation.
= Law of Segregation (Second Law) : This law states that though the parents contain two alleles during gamete formation the factors or alleles of a pair segregate from each other, such that gamete receives only one of the two factors.
= Hence, the alleles do not show any blending and both the characters are recovered as such in the `F_2` generation, though one of these is not seen in the `F_1` generation