ACT: Autosomal Linkage:
Crossing Over and Chromosome Mapping
Crossing Over
1.
Gene C and D are linked and are 15 map units apart.
If individuals with these
genes were mated and 1000 offspring were produced, how many of those
offspring would be expected to be recombinants?
15 map units = 15% chance of crossover = 15% recombination rate.
This means that if there are 1000 offspring 15% of them or 150 offspring
would exhibit recombined characteristics.
2.
In tomatoes the following allele information applies to two known linked genes:
Gene for fruit shape
Gene for fruit skin
Dominant
Round (R)
Smooth ( S)
Recessive
Long (r)
‘Peach’ (s)
In a test cross with a tomato plant heterozygous for both fruit shape and fruit skin
, the following were the offspring results:
Round and Smooth
Long and Smooth
Round and Peach
Long and Peach
12
123
133
12
a.
Which alleles are completely linked?
Long & Smooth
Round & Peach
b.
Which alleles are recombined?
Round & Smooth
Long & Peach
c.
What is the % Cross Over between these two genes?
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- Spring '17
- alice chu
- Genetic linkage, Long hair, map units
