10.2 inheritance Flashcards
what are LINKED gene loci?
linked genes – genes found on the SAME CHROMOSOME
the closer the loci of two linked genes,
the less frequently they are separated by crossing over
how do linked genes affect each other during allele inheritance
the allele inherited for one gene does NOT affect which allele will be inherited for the other gene
how are recombinants involving linked genes drawn?
t b (one chromosome)
one loci
each letter codes for a different trait
two distinct possibilities for the genotype of a heterozygous parent in a LINKAGE PROBLEM (linked genes)
tb
and
tB
how to test for linkage (test cross)
heterozygous parent x homozygous recessive parent
- not linked: follow mendels law of indep assortment, 1:1:1:1
- non-mendelian ratios obtained, genes likely to be linked
during a test cross to test for linkage, the lower the recombinant frequency,…
the closer the linked genes are on the chromosome
what is sex-linkage
any gene found on the sex chromosomes
what is autosomal linkage
two genes found on the same autosomal chromosome (a non-sex chromosome)
test for recombinant phenotypes
test cross (homozygous recessive for both traits)
polygenic traits
more than one gene may affect a single trait
pleiotropic genes
a single gene may affect multiple traits
epistatic genes
a gene may impact the expression of another gene
penetrance of the allele
some alleles are not expressed in all individuals
expressivity of the allele
some alleles are expressed with varying intensity
