Mega Genetics Review: Mendelian and non-Mendelian Genetics

Mendelian Genetics

A type of inheritance pattern where dominant alleles express dominant traits.

Genotype

The genetic makeup of an individual, represented by alleles.

Phenotype

The observable characteristics or traits of an organism.

Homozygous

An organism with two identical alleles for a trait.

Heterozygous

An organism with two different alleles for a trait.

Punnett Square

A diagram used to predict the outcome of genetic crosses.

Monohybrid Cross

A genetic cross that involves one trait.

Dihybrid Cross

A genetic cross involving two different traits.

Incomplete Dominance

A genetic situation in which one allele is not completely dominant over another, resulting in a blended phenotype.

Codominance

A genetic situation where both alleles are fully expressed in the phenotype.

Polygenic Traits

Traits controlled by multiple genes, leading to a range of phenotypes.

Pleiotropic Traits

A single gene that influences multiple phenotypic traits.

Epistasis

When the expression of one gene is affected by another gene.

Sex-linked Traits

Traits associated with genes located on sex chromosomes.

Pedigree

A diagram that shows genetic relationships and traits through generations.

Multiple Alleles

More than two alleles for a genetic trait exist in a population.

Dominant Allele

An allele that expresses its phenotype even in the presence of a recessive allele.

Recessive Allele

An allele that is only expressed phenotypically when it is present in homozygous form.

Gametes

Reproductive cells that carry half the genetic information, either from the mother or father.

Alleles

Different forms of a gene that can exist at a specific locus.

Monohybrid Cross Example: Tt x Tt What are the genotypic ratios of the offspring?

(A: 1 TT : 2 Tt : 1 tt) (B: 25% TT, 50% Tt, 25% tt)

Monohybrid Cross Example: Aa x aa What are the genotypic ratios of the offspring?

(A: 1 A: 1 a) (B: 50% A, 50% a)

Dihybrid Cross Example: RrYy x RrYy What are the genotypic ratios of the offspring?

(A: 1 RRYY : 2 RRYy : 2 RrYY : 4 RrYy : 1 rrYY : 2 rrYy : 1 rryy)

Dihybrid Cross Example: AaBb x AaBb What are the phenotypic ratios of the offspring?

(A: 9:3:3:1 ratio for dominant and recessive traits)

Monohybrid Cross Example: BB x Bb What are the phenotypic percentages of the offspring?

(A: 75% Dominant trait, 25% Recessive trait)

Dihybrid Cross Example: TtYy x TtYy What are the genotypic percentages of the offspring for the combinations?

(A: 1 TTYY : 2 TTYy : 2 TtYY : 4 TtYy : 1 ttyy)

Monohybrid Cross Example: hh x HH What are the phenotypic ratios of the offspring?

(A: 100% Hh)

Dihybrid Cross Example: AaBb x aabb What are the genotypic ratios of the offspring

(A: 1 AaBb : 1 Aabb : 1 aaBb : 1 aabb)