Mr Medeiros Genetics

Genetics

The scientific study of heredity

Heredity

The passing on of physical or mental characteristics genetically from one generation to another

Trait

A specific characteristic that varies from one individual to another (ex: brown hair, blue eyes, tall, curly hair)

Gregor Mendel

Austrian monk 1822-1884 who conducted the first important study of heredity using pea plants, he is often referred to as the father of genetics

Dominant trait

Masks other traits, will always show if present, represented by a capital letter

Recessive trait

Does not show if the dominant allele is present, only shows if both alleles are recessive, masked by dominant traits, represented by a lowercase letter

Genotype

The allele combination an organism has in its genetic make up (ex: Tt, ss, GG, Ww, etc)

Phenotype

The physical characteristics of an organism; the way it looks (ex: curly hair, straight hair, blue eyes, green eyes, etc)

Homozygous

Two identical alleles for a particular trait (ex: TT or tt)

Heterozygous

Two different alles for a particular trait (ex: Tt)

Punnett square

Diagram showing the gene combinations that might result from a genetic cross; used to calculate the probability of inheriting a particular trait

Purebreed/Truebreed

Same meaning as homozygous

Carrier/Hybrid

Same meaning as heterozygous

Allele

The different forms of a trait, each trait has at least two alleles / two letters (ex: eye color could be brown, blue, green, or hazel)

Codominance

a genetic inheritance pattern where two different alleles (versions of a gene) are fully, equally, and simultaneously expressed in an individual's phenotype. Unlike dominant/recessive relationships, neither allele masks the other