Genetics

Examples in real life

What does homo mean?

Terms to know: Trait Gene Heredity Allele Recessive Dominant Homozygous Heterozygous Genotype Phenotype

Passing of from one generation to the next. Heredity Passing of from one generation to the next. TraitS

Inherited forms of a characteristic. TraitS Inherited forms of a characteristic. Examples: Flower color, Eye color, hair color, etc.

Traits All must have at least 2 . Genes One from each parent.

Genes? Blonde hair Brown hair Blue eyes Green eyes Remember: 2 genes for each TRAIT

Allele Different forms of each gene Blonde hair (blonde allele) Brown hair (brown allele)

Sometimes one gene overpowers the other. Dominant Recessive Sometimes one gene overpowers the other.

Dominant Gene overpowers the recessive gene Always shows up if present Gene designated by captial letter Ex: D

Recessive gene that gets overpowered Only shows up if 2 recessive genes are present gene designated by lower case letter Ex: d

the genes of a pair are different Ex: Dd Heterozygous the genes of a pair are different Ex: Dd

the genes of a pair are the same Ex: DD or dd Homozygous the genes of a pair are the same Ex: DD or dd

The animal has the same genes for the trait. What did homo mean? The animal has the same genes for the trait.

The actual gene combination Ex: DD Dd dd Genotype The actual gene combination Ex: DD Dd dd

The physical appearance Ex: Black Black Red Phenotype The physical appearance Ex: Black Black Red

This knowledge can be used to manage or predict physical outcomes.

Use a Punnet Square

Example: Tongue rolling is dominant (T) No tongue rolling is recessive (t) Cross 2 heterozygous people: Tt T t TT Tt Tt tt

Genotype 1 2 1 T t TT Tt tt # of homozygous rollers # of heterozygous rollers 2 # of homozygous non rollers 1

TT Tt tt Phenotype # of rollers 3 1 # of non rollers

Review Dominant overpowers Recessive Homozygous - PP pp Heterozygous – Pp Genotype – the genes Phenotype - appearance