Study Notes on Genetics - Genotype, Phenotype, Punnett Squares, and Alleles (chapter 18 video 3)

Genotype

what is the genetic constitution (alleles ) inherited from parents (e.g., Tt)

Phenotype

what is the observable trait (e.g., tall) resulting from the genotype-environment interaction; Punnett squares are used to predict these outcomes.

Punnett square

A diagram used to predict the genetic outcomes of a cross between two organisms, showing the possible allele combinations in the offspring.

What determines a phenotype?

The genotype and its interaction with the environment.

Dominant allele

An allele that expresses its trait even in the presence of a recessive allele; it masks the effect of the recessive allele in a heterozygous genotype.

Recessive allele

An allele that is masked by a dominant allele and only expressed in the phenotype when two copies are present.

Homozygous

having two identical alleles for a particular gene.

Heterozygous

Having two different alleles for a specific gene, one dominant and one recessive.

Homozygous dominant

Having two identical dominant alleles for a specific gene.

Homozygous recessive

Having two identical recessive alleles for a specific gene.

sex linked traits

Traits that are determined by genes located on sex chromosomes, often affecting one sex more than the other.

Multiple alleles

The presence of more than two alleles for a specific gene in a population, allowing for multiple phenotypes.

codominance

Both alleles show their effects but they’re not blended

Incomplete dominance

Both alleles blend their effects (they blend)