Genetics and Heredity

What is heredity? The passing on of characteristics from parents to offspring. Genetics is the branch of biology that studies heredity the characteristics that are inherited are traits.

Father of Modern Genetics Gregor Mendel – Augustinian Monk in 1856 to 1863 Experimented on heredity and traits First person to be able to predict traits

Mendel’s Subject He chose pea plants, which reproduce sexually, which means they have two distinct sex cells, male and female. sex cells are called gametes. the transfer of male pollen grains to the pistil of a flower is called pollination the uniting of male and female gametes is called fertilization

Crosses A hybrid is the offspring of parents that have different forms of a trait, such as tall and short. Mendel first did monohybrid crosses, which means he was looking at only one trait.

Mendel’s crosses

The rule of dominance Every trait is coded for by two genes the genes have different forms called Alleles. Alleles are either dominant, recessive or co-dominant

the law of segregation That when gametes are formed, the parent separates their two genes that code for the same trait. So the child gets one from each parent.

phenotype the way an organism looks and behaves is called it’s phenotype. example: what color are your eyes, or your hair? what you see is the phenotype.

Genotype the gene combination an organism contains is known as genotype.

Homozygous vs. Heterozygous an organism that is homozygous for a trait has two alleles for the trait that are the same. an organism that is heterozygous for a trait has two different alleles (dominant and recessive).