Category 4 – STAAR Review GENETICS REVIEW Category 4 – STAAR Review

Genetics and Heredity Genetics: The study of heredity. Gregor Mendel: Father of genetics.

Genetics and Heredity Genes that code for different versions of a trait (For example: hitchhikers’ thumb or regular thumb) are called alleles.

Phenotypes The physical appearance of an organism. Example: tongue roller , blood type, no hitchhikers’ thumb. Blood Types A, B AB, O

Genotypes The alleles a person actually has and is shown by the use of capital and lowercase letters. Example: TT, Tt, tt,

Alleles can be… DOMINANT or recessive Dominant alleles always show their trait, no matter what the other trait from the other parent is. Dominant alleles are shown as capital letters. Examples: T= Hitchhiker’s Thumb

Alleles can be… DOMINANT or recessive Recessive alleles do not show their trait unless both alleles are recessive. Recessive alleles are shown as lower case letters. Example: t= Regular Thumb

Genotypes Homozygous- an organism has two alleles that are the same (Homo=same) Example: TT, tt

Genotypes Heterozygous- an organism has two different alleles (Hetero= Different) Example: Tt

Natural Selection, Charles Darwin, & Artificial Selection https://www.youtube.com/watch?v=2FNx0elesus https://www.youtube.com/watch?v=eEUvRrhmcxM

Fundamentally Genetics Lab Tongue Rolling Earlobes that hang Attached Earlobes Widow’s Peak