Question

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Explain the laws postulated by Mendel based upon his Monohybrid crosses.​

Answer 1

$\huge\underline\mathfrak\pink{Answer-}$

Mendel postulated two laws of genetics based upon the observations of monohybrid crosses :

a) Law of Dominance

b) Law of segregation

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1) $\large\underline\blue{\sf{Law\:Of\:Dominance-}}$ Out of two factors only one is able to express itself in the phenotype of Organisms and not other. The factor which is expressible is called a Dominant factor while the other is called a recessive factor.

Explanation : In the condition of ( Tt ) only the effect of tall is visible and not of dwarfness. So in F1 generation no medium sized plants appeared. Only tall plants were seen. It must be due to the dominant effect of (T) factor over (t) factor, which represses the effect of (t) when present in it.

2) ) $\large\underline\blue{\sf{Law\:Of\:Segregation-}}$ According to this law, the factors of any trait are segregated ( separated ) from each other so that any gamete recieves only one out of two factors.

In other sense, the gametes are pure in having half of the factors. So the gametes are pure and also the law is called as the law of purity of gametes.

Explanation : Pure tall is having ( TT ). These are separated and fuse randomly with separated factors. (t) and (t) of dwarf ( tt ) plant. In F1 generation, all the plants have genotypes - ( Tt ). This is possible only when the factors separated during gamete formation.

Answer 2

Explanation:

Mendel discovered that by crossing true-breeding white flower and true-breeding purple flower plants, the result was a hybrid offspring. Rather than being a mix of the two colors, the offspring was purple flowered. He then conceived the idea of heredity units, which he called “factors”, one of which is a recessive characteristic and the other dominant. Mendel said that factors, later called genes, normally occur in pairs in ordinary body cells, yet segregate during the formation of sex cells. Each member of the pair becomes part of the separate sex cell. The dominant gene, such as the purple flower in Mendel’s plants, will hide the recessive gene, the white flower. After Mendel self-fertilized the F1 generation and obtained an F2 generation with a 3:1 ratio, he correctly theorized that genes can be paired in three different ways for each trait: AA, aa, and Aa. The capital A represents the dominant factor while the lowercase a represents the recessive.