It is the study of genes, genetic variation, and heredity in living organisms.
The genetic information lies within the cell nucleus of each living cell in the body.
Mendel"s Laws of genetics
Law of Dominance
In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the
next generation. Offspring that are hybrid for a trait will have only the dominant trait in the
Law of Segregation
During the formation of gametes (eggs or sperm), the two alleles responsible for a trait separate from
each other. Alleles for a trait are then "recombined" at fertilization, producing the genotype for the
traits of the offspring.
Law of Independent Assortment
Alleles for different traits are distributed to sex cells (& offspring) independently of one another.
Sex Determination and its type
It is a biological system that determines the development of sexual characteristics in an organism.
Three important chromosomal sex-determining systems:
1. XX-XY system
2. XX-XO system
3. ZZ-ZW System
Sex Determination in Human
Sex is determined by the possession of certain sexual characteristics which are governed by sex
These sex genes reside in sex chromosomes in one"s body and in human; there are two types of
sex chromosomes, X and Y.
For human, XY are found in a male and XX in a female.