Based on his experiments of monohybrid and dihybrid cross, Mendel proposed three important laws which are now called Mendel's Laws of Heredity.
i. Law of dominance and recessiveness
ii. Law of segregation or Law of purity of gametes
iii. Law of independent assortment
i. Law of Dominance
The law of dominance and recessiveness states : "When two homozygous individuals with one or more sets of contrasting characters are crossed, the characters that appear in the F1 hybrid are dominant and those that do not appear in F1 are recessive characters".
ii. Law of Segregation or Law of Purity of Gametes
The Law of segregation states that "When a pair of contrasting factors or genes or allelomorphs are brought together in a heterozygote or hybrid, the two members of the allelic pair remain together without mixing and when gametes are formed the two separate out, so that only one enters each gamete".
This law though it was a conception originally and propagated by Mendel, now it has been confirmed by cytological studies. Dominance or no dominance segregation holds good for all cases.
iii. Law of independent Assortment
Law of independent assortment states : "In case of inheritance of two or more pairs of characters simultaneously, the factors or genes of one pair assort out independently of the other pairs". Mendel gave this law based on his dihybrid cross experiment. Here the total number of individuals in F2 will be sixteen which occur in a ratio of 9:3:3:1 where two parental classes and two new combinations will be produced.
i. Law of dominance and recessiveness
ii. Law of segregation or Law of purity of gametes
iii. Law of independent assortment
i. Law of Dominance
The law of dominance and recessiveness states : "When two homozygous individuals with one or more sets of contrasting characters are crossed, the characters that appear in the F1 hybrid are dominant and those that do not appear in F1 are recessive characters".
ii. Law of Segregation or Law of Purity of Gametes
The Law of segregation states that "When a pair of contrasting factors or genes or allelomorphs are brought together in a heterozygote or hybrid, the two members of the allelic pair remain together without mixing and when gametes are formed the two separate out, so that only one enters each gamete".
This law though it was a conception originally and propagated by Mendel, now it has been confirmed by cytological studies. Dominance or no dominance segregation holds good for all cases.
iii. Law of independent Assortment
Law of independent assortment states : "In case of inheritance of two or more pairs of characters simultaneously, the factors or genes of one pair assort out independently of the other pairs". Mendel gave this law based on his dihybrid cross experiment. Here the total number of individuals in F2 will be sixteen which occur in a ratio of 9:3:3:1 where two parental classes and two new combinations will be produced.
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