Genetics Flashcards
Genes
Sequences of DNA that code for heritable traits
Alleles
Alternative forms of genes
Locus
Location on a specific chromosome
Complete dominance
Dominant allele masks the recessive allele i.e. yellow peas over green peas
Codominance
More than one dominant allele exists for a given gene i.e. blood type AB (IAIB)
Incomplete Dominance
Heterozygote expresses a phenotype that is a mixture of both homozygous genotypes. i.e.
Penetrance
The proportion of the population with a given genotype that actually express the phenotype
Expressivity
Varying phenotypes despite identical genotypes
Law of Segregation
- Organism has 2 alleles for each gene
- The two alleles segregate during meiosis, resulting in gametes that carry only one allele for any inherited trait
- Expressed allele is dominant; silent is recessive
Law of Independent Assortment
the inheritance of one gene does not affect the inheritance of another
Silent mutation
Change in nucleotide has no effect on protein product.
Missense mutation
Change in nucleotide causes change in one amino acid in protein
Nonsense mutation
Change in nucleotide results in insertion of a stop codon; most deleterious and damaging
Frameshift mutation
Insertions or deletions that shift the reading frame and change amino acid sequence
Monohybrid cross
1: 2:1 genotype ratio
3: 1 phenotype ratio
Test Cross
Used to determine genotypes of parent based off phenotypes
