genetics, punnet squares, codominant and multiple alleles

Genetics

The study of the process of heredity (inheritance of traits)

Trait

Characteristic that can be passed from parent to offspring

Dominant allele

Form of a gene that is fully expressed even when two different alleles are present, represented by capital letters

Recessive allele

Form of a gene that is not expressed when paired with a dominant allele, represented by lowercase letters

Genotype

The actual gene pair you have for a trait. EX: bb

Phenotype

The physical appearance/traits you see

Homozygous

Genes in a pair are the same. EX TT or tt

Heterozygous

genes in a pair are different. EX Tt

Pedigrees

Used to show patterns of inherited traits in a family

Carrier

Someone who carries the trait, but does not display any symptoms, typically heterozygous genotype

What represents a circle on a pedigree chart?

Female

What represents a square on the pedigree chart

Male

If the circle is not shaded in on a pedigree chart, what is that?

Normal female

If the circle is shaded in on a pedigree chart, what is that?

Affected female

If the circle is half shaded and half not shaded on a pedigree chart, what is that?

Female carrier

If the square is not shaded in on a pedigree chart, what is that?

Normal male

If the square is shaded in on a pedigree chart, what is that?

Affected male

If the square is half shaded and half not shaded on a pedigree chart, what is that?

Male carrier

Incomplete dominance

Neither allele is dominant, so the traits blend together in the offspring, resulting in a mix

Co-dominant

Both alleles in the heterozygote are fully expressed

Multiple alleles

3 or more different forms of a gene controlling a specific trait

What is human blood type controlled by?

Multiple alleles inheritance

Type A blood

IAIA OR IAi

Type B blood

IBIB or IBi

Type AB blood

IAIB

Type O blood

ii