Linked genes

Question 1

define locus

Answer 1

the location of a gene/allele on a chromosome

Question 2

what is dihybrid inheritance

Answer 2

two characteristics that are each controlled by one gene with two or more alleles
each gene is at a different locus
e.g. tall (TT) green flowered (GG) plant bred with a short (tt) yellow flowered (gg) plant

Question 3

what are the inheritance ratios in the F2 generation if genes are linked and genes not linked

Answer 3

linked genes-
ratio 3:1
genes not linked:
ratio 9:3:3:1 (all possible mixed types produced)
- has to have a large sample size

Question 4

when will genes tend to be passed as a pair to the same gamete

Answer 4

when any two genes with a locus on the same chromosomes are linked together
during crossing over they will be switched together

Question 5

how many copies of a gene will males inherit if the gene is found on the X chromosome and how many alleles to have a recessive phenotype

Answer 5

males inherit one copy of the gene since they have XY chromosomes unlike females who have XX
men only need to inherit one recessive allele in order to have the recessive allele on the chromosome XrY

Question 6

how many copies of a gene will females inherit if the gene is found on the X chromosome and how many alleles to have a recessive phenotype

Answer 6

females inherit two copies of the gene since they have XX chromosomes unlike men who have XY
females need to inherit two recessive alleles in order to have the recessive phenotype XrXr (if it was XRXr it would be dominant)