1. Department ~ Genetics & Plant breeding H.O.D- Dr. AIOK SINGH

2. Mendel's laws Presented by- Mukesh Kumar Singh

3. 1. INTRODUCTION 2. GENETICS TERMINOLOGY 3. LAW OF SEGREGATION 4. LAW OF INDEPENDENT ASSORTMENT

4. WAS MENDEL ?

5. 20 July 1822 PLACE Austria (Brunn) NOW “Czechoslovakia” (Bruno)

6. Austrian ALMA MATER University of Olomouc University of vienna &

7. Father of genetics FIEALDS Genetics

8. (1)*Law of segregation (2)*Law of independent assortment In(1865) *DIED* 6 January 1884(Aged 61)

9. CROSS- Cross is mating of two or more individual strain have in different genotype are called cross; GENOTYPE- The genetic constitution of an organism are called genotype. PHENOTYPE- Externally appearance of an individual are called phenotype. HETEROZYGOUS- An individual have in dissimilar allele of a gene. HOMOZYGOUS- An individual have in two or more identical allele of a same gene.

10.  Character: heritable feature (i.e., fur color)  Trait: variant for a character (i.e. b rown)  True-bred: all offspring of same variety  Hybridization: crossing of 2 diff erent true-breds We label the different generatio ns of a cross as:  P generation (parents)  F 1 generation (1st filial generation)  F 2 generation (2nd filial generation)

11. This law states that allele “segregate from each other during gamete formation and pass an different gamete in equal number” LAW OF SEGREGATION

12. LAW OF SEGREGATION FIG-

13.  Example: The gene for seed shape in pea plants exists in two forms, one form or allele for round seed shape (R) and the other for wrinkled seed shape (r). The round seed shape is dominant and the wrinkled seed shape is recessive. A homozygous plant contains either of the following alleles for seed shape: (RR) or (rr).geneallele

14.  The (RR) genotype is homozygous dominant and the (rr) genotype is homozygous recessive for seed shape.genotype  In the image above, a monohybrid cross is performed between plants that are heterozygous for round seed shape.monohybrid cross

15.  The predicted inheritance pattern of the offspring results in a 1:2:1 ratio of the genotype. About 1/4 will be homozygous dominant for round seed shape (RR), 1/2 will be heterozygous for round seed shape (Rr), and 1/4 will have the homozygous recessive wrinkled seed shape (rr). The phenotypic ratio in this cross is 3:1.genotype  About 3/4 of the offspring will have round seeds and 1/4 will have wrinkled seeds.

16. This is law states that when two pairs of gene enter in f1 combination both of them,have there Independent dominant effect. The gene segregate When gamete are from but the assortment occurs Randomly and quit freely.

18.  Mendel performed dihybrid crosses in plants that were true-breeding for two traits. For example, a plant that had round seeds and yellow seed color was cross-pollinated with a plant that had wrinkled seeds and green seed color.dihybrid crossestrue-breeding  In this cross, the traits for round seed shape (RR) and yellow seed color (YY) are dominant. Wrinkled seed shape (rr) and green seed color (yy) are recessive.

19.  The resulting offspring (or F1 generation) were all heterozygous for round seed shape and yellow seeds (RrYy). This means that the dominant traits of round seed shape and yellow color completely masked the recessive traits in the F1 generation.

20.  The F2 Generation: After observing the results of the dihybrid cross, Mendel allowed all of the F1 plants to self-pollinate. He referred to these offspring as the F2 generation.  Mendel noticed a 9:3:3:1 ratio in the phenotypes. About 9/16 of the F2 plants had round, yellow seeds; 3/16 had round, green seeds; 3/16 had wrinkled, yellow seeds; and 1/16 had wrinkled, green seeds.phenotypes