Genetics Flashcards
Complete dominance
When only one dominant and one recessive allele exist for a given gene. Dominant will mask recessive.
Codominance
When more than one dominant allele exists for a given gene. Example: AB blood type.
Incomplete dominance
When a heterozygote expresses a phenotype that is intermediate between the 2 homozygous genotypes. Example: Mating of certain Red and White flowers to get Pink.
Penetrance
proportion of the population with a given genotype who actually express the phenotype
Expressivity
Different manifestations of the same genotype across the population
Mendel’s 1st law
Law of segregation
Genes exist as alleles.
An organism has 2 alleles for each gene
Separation of homologous chromosomes during anaphase I
Mendel’s 2nd law
Law of independent assortment
The inheritance of one gene does not affect the inheritance of another gene
Wild type allele
The alleles that are considered normal or natural in the population
Point mutations
When a nucleotide in DNA is swapped for another
Silent, missense, or nonsense
Silent mutation
when the change in nucleotide has no effect on the final protein synthesized from the gene
Missense mutation
When the change in nucleotide results in substituting one amino acid for another in final protein
Nonsense mutation
Change in nucleotide results in substituting in a stop codon for an amino acid in final protein
Frameshift mutations
When nucleotides are inserted into or deleted from the genome. This shifts the reading frame and changes the sequence or results in premature truncation
Chromosomal mutations
Larger scale mutation in which large segments of DNA are affected
Deletion, duplication, inversion, insertion, translocation
Deletion mutation
When a large segment of DNA is lost from a chromosome
