GENETICS PRESENTED BY; ABU BAKAR SIKANDER (Medical Laboratory Technology)

GENETICS Genetics is the science of heredity and variation in living organisms. GENE is the basic unit of biological information. ALLELES are the partners of a gene pair.

Types of GENETICS 1.Molecular Genetics: (concerns with the molecular mechanisms governing the gene expression) 2.Biochemical Genetics: (concerns with the chemical and physical nature of genes and the mechanism by which they control the development and maintenance of the organism) 3.Clinical Genetics: (the study of genetic factors influencing the occurrence of pathologic condition)

Mendel and Genetics Modern science of genetics, which seeks to understand the process of inheritance, began with the work of Gregor Mendel in the mid- nineteenth century

Mendel’s Work on GENETICS Gregor Johann Mendel ( ) laid the foundation of Classical Genetics. He performed series of experiments on garden pea, Pisum sativum in his garden for eleven years ( ). Mendel formulated two Laws: 1) law of segregation 2) law of independent assortment

LAW OF SEGREGATION According to law of segregation, “the two coexisting alleles for each trait in an individual segregate (separate) from each other at meiosis, so that each gamete receives only one of the alleles.” Alleles unite again Randomly during fertilization of gametes when zygote is formed.

LAW OF SEGREGATION R r Rr 1/2 F1F1 Gametes

Law Of Independent Assortment “When two contrasting pairs of traits are followed in the same cross, their alleles assort independently into gametes". Alleles of one pair inherit independently of alleles of the other pair. The distribution of alleles of one trait into gametes has no influence on the distribution of alleles of the other trait

LAW OF INDEPENDENT ASSORTMENT RRYY rryy RrYy RRYY RRYyRrYYRrYy RRYyRRyyRrYyRryy RrYYRrYyrrYYrrYy RrYyRryyrrYyrryy RY RyrYry Ry rY ry 9:3:3:1 P 1 generation F 1 generation F1F1 F1F1

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