lecture 16 Flashcards
genetic linkage and recombination
what is occurring when two or more genes are inherited together?
gene linkage
where must the loci of linked genes be relative to one another?
on the same chromosome
what does NOT happen when genes are completely linked?
crossover
in cis-configuration, genes are coupled. what does that mean?
the two normal alleles are on one chromosome and the mutant alleles are on the other
in trans-configuration, genes are repulsed. what does that mean?
each chromosomes contains one normal allele and one mutant allele
what will a cis-configuration test cross of two genes result in?
only repeats of parental phenotypes
what does a trans-configuration test cross of two genes result in?
only non-parental phenotypes can be inherited; all recombinants
what is the equation for recombinant frequency?
of recombinants/ # of total progeny
what is the exchange of genetic material between non-sister chromatids?
crossing over
what is the point of crossing over called?
chiasmata
what type of chromosomes interact during crossing over?
homologous chromosomes
what does the frequency of recombination depend on?
the distance between the loci
if linked genes are closer together, does the RF increase or decrease?
decrease
if there is a double crossover BETWEEN the two loci of linked genes, what happens to the phenotype?
no change
