Chapter 12- Genetics and Evolution Flashcards
homologues
each human possesses two copies of each chromosome (except the male sex chromosome)
hemizygous
genotypical situation in which only one allele is present for a given gene (as is the case for parts of the X chromosome in males)
incomplete dominance
heterozygote expresses a phenotype that is intermediate between the two homozygous geneotypes.
codominance
more than one dominant allele exists for a given gene
penetrance
population measure. proportion of individuals in the population carrying the allele who actually express the phenotype
expressivity
different manifestations of the same genotype across the population
two mechanisms that allow for greater genetic diversity in offspring
segregation and independent assortment (also crossing over)
transforming principle
nonvirulent bacteria acquired the ability to form smooth capsules from the dead virulent bacteria (Griffiths experiment)
transposons
small piece of DNA that can insert/remove itself from DNA
silent mutation
change in nucleotide has no effect on final protein synthesized from the gene
degeneracy
wobble in genetic code in the third nucleotide of a codon
missense mutation
change in nucleotide results in substituting one amino acid for another in the final protein
nonsense mutations
occur when change in nucleotide results in substituting a stop codon for an amino acid in the final protein
chromosomal mutations
larger-scale mutations in which larger segments of DNA are affected
translocation mutations
occur when a segment of DNA from one chromosome is swapped with a segment of DNA from another chromosome
deleterious
detrimental (one class is “inborn errors of metabolism)
inborn errors of metabolism
class of deleterious mutations. defects in genes required for metabolism.