Mendelian Genetics: Laws and Dominance Types

Law of Segregation

Gametes receive one randomly selected allele.

Law of Independent Assortment

Genes sort independently into gametes.

Complete Dominance

Dominant allele determines phenotype in offspring.

Incomplete Dominance

Mixed phenotype from dominant and recessive traits.

Overdominance

Heterozygous genotype is more dominant than homozygous.

Co-dominance

Both alleles express simultaneously in phenotype.

Multiple Alleles

More than two alleles exist for a gene.

Lethal Genes

Genes that can cause organism death.

Recessive Lethal

Lethal only in homozygous recessive condition.

Dominant Lethal

Lethal with just one dominant allele present.

Recessive Epistasis

Homozygous recessive gene masks other genes (9:3:4).

Dominant Epistasis

Dominant gene masks other genes (12:3:1).

Linked Genes

Genes that cannot be separated during inheritance.

Thomas Hunt Morgan

Pioneer in genetics using Drosophila melanogaster.

Parental Types

83% offspring resemble parental genotypes.

Recombinant Types

17% offspring show new allele combinations.

Complete Linkage

Genes inherited together, 100% parental types.

Incomplete Linkage

Results in 1:1:1:1 offspring ratios.