Week 4 Flashcards
What happens when there are more than 2 pairs of gametes?
Chromosome pairs bah e independently of each other and assort into different gametes
What is the phenotypic ratio of F2 of a dihybrid cross with complete dominance?
9:3:3:1
What is epistasis?
The effect that gene interaction has on the expression of a phenotype how the presence of different alleles may mask or enhance the expression of a certain phenotype
What would the dihybrid ratio of dominant epistasis look like?
12:3:1
What does a cis arrangement look like?
a b
What does a trans arrangement look like?
a B
What are recombinants and how common are they?
Recombinants occur when loci crossover, recombinants generally occur in lower numbers
What causes crossovers?
The relative distance between loci, the greater the distance, the more likely the change of recombination
What is the MAP distance?
The relative distance between loci, 1 cM = 1% recombination
MAP distance =
No. of recombinant/ total offspringX 100
What is a test cross?
A cross between a genotype and a homozygous recessive
What is autosomal linkage?
Linked genes do not assort independently, or gametes are not produced in equal frequency
Define non-recombinant offspring
Offspring resulting fruit m a gamete in which the same allelic arrangement in the parent is seen
Define recombinant offspring
Offspring resulting from gametes with different allelic arrangement to the parent
What is a three point test cross?
A cross involving three loci on a chromosome
What is a single recombinant?
Offspring resulting from one gamete cross in one region in a three point test cross
