This document summarizes several principles of Mendel's laws of inheritance: 1. Mendel conducted hybridization experiments on peas from 1856-1863 and proposed the basic laws of inheritance in organisms. 2. Inheritance follows patterns of dominance, with one allele expressing itself over the other in a gene pair. Mendel also described the law of segregation where alleles do not blend but are recovered unchanged in subsequent generations. 3. The principle of independent assortment holds that different genes independently separate from one another during the formation of reproductive cells, as Mendel first observed in his pea plant experiments.

1. Principle of
inheritance

2. Mendel’s law of inheritance
 Gregor Mendel, conducted hybridization
experiments on garden peas for seven years
(1856-1863) and proposed the laws of inheritance
in living organisms.

3. Inheritance of one gene
Single gene-pair inheritance occurs when a trait is linked to one gene-pair
that consists of two alleles. This is also referred to as Mendelian inheritance.
An allele is one part of the gene-pair.

4. Test Cross
 In typical test cross organism showing a dominant phenotype is crossed with
the recessive parent instead of soft cell crossing

5. Law of dominance
Out of two factors or alleles representing different traits of
a character, only one expresses itself.

6. Law of segregation
 The alleles do not show any blending and both the
character are recovered as such in the F2 generation
through one of these are not seen at the F1 stage

7. Incomplete dominance
It is the phenomenon of nither of the two alleles of a gene being dominated
over each other so that when both of them are togather, a new phenotype is
formed which is somewhat intermediate between the independent
expression of the two alleles.

8. Co-dominance
 The genes (I) has three alleles IA , IB and i. the alleles IA and IB produce
slightly different form of the sugar while allele i does not produce any sugar.
Because humans are diploid organisms, each person possesses any two of the
three I gene alleles. IA and IB are completely dominant over i , in other words
when IA and i are present only IA expresses (because i does not produce any
sugar), and when IB and i are present their own types of sugers: this is
because of co-dominance . Hence red blood cells have both A and B types of
suger.

9. Inheritance of two genes
/ didybrid cross
 Dihybrid cross is a cross between two pure lines (varieties, strains) that differ
in two observed traits. In Mendelian sense, between the alleles of both these
loci there is a relationship of complete dominance - recessive.

10. Law of independent assortment
 The Principle of Independent Assortment describes how different genes
independently separate from one another when reproductive cells develop.
Independent assortment of genes and their corresponding traits was first
observed by Gregor Mendel in 1865 during his studies of genetics in pea
plants.

11. Prepared by
nitika
Sharma