Flashcards in Multiple-Locus Transmission Patterns Deck (22)
Mendel began his experiments with crosses involving...
one locus and two alleles
Mendelian ratio for a cross of double heterozygotes with random segregation (not linked)
Mendel's second law
alleles at different loci and passed on independently
when does Mendel's second law breakdown?
when two genes are on the same chromosome and close together
alleles are not passed on independently, and are considered "linked"
two genes on the same chromosome
does syntenic mean linked?
not always, they have to be close together and syntenic to be linked
how to calculate offspring genotype and phenotype frequencies in non-linked loci?
when loci are linked, their association in transmission is...
stronger the closer together they are
when is there more recombination?
when loci are farther apart
when is there less recombination?
when loci are closer together
can linkage be detected and recombination quantified in a two-locus testcross?
recombination frequency is typically calculated from...
two-locus testcross data
divide total recombinants by total offspring
how can recombination frequencies can be expressed...
as a decimal fraction
one = 1% recombination
(cM) not (cm)
another word for recombination events
are crossovers random?
yes, pretty much
crude approximation ...
one cM equals about one Mb (megabase) of DNA
does the real crossover rate vary?
where is crossover rate lowest?
around centromeres and tips of the arms
are recombination rates (frequencies) additive?
crossover rates of less than 10%...
loci close together
related linearly to physical distance