SHOW ALL WORK In green turtles, an odd number of plates on their shell is domina
ID: 34046 • Letter: S
Question
SHOW ALL WORK
In green turtles, an odd number of plates on their shell is dominant over an event number of plates. On the same chromosome is a gene for ear spot color with red being dominant over orange. On this same chromosome is the gene for strip color on the body with yellow being incompletely dominant with blue strips. These turtles were crossed in a breeding experiments and the following data was determined.
Cross One:
ODD, RED (heterozygote) with a EVEN, ORANGE
950 odd, red
990 even, orange
25 odd, orange
38 even, red
Cross Two:
ODD, Green (heterozygote) with a EVEN, YELLOW
328 odd, green
316 even, yellow
68 even, green
79 odd, yellow
Cross Three:
RED, Green (heterozygote) with a ORANGE, YELLOW
421, red, green
387, orange, yellow
71, red, yellow
68, orange, green
Determine the recombination rate for each trait and make a map of the chromosome showing the spatial relationships between the genes
Explanation / Answer
a) Cross 1:
For the trait odd red the recombination rate can be calculated by calculating the progeny that shows their separation i.e.
Odd red recombination rate= 25+38/ 2003* 100
=63/2003*100 = 3.145%
Cross 2:
For the trait odd green the recombination rate can be calculated by calculating the progeny that shows their separation i.e.
Odd green recombination rate= 68+79/ 791* 100
= 147/791*100
= 18.58%
Cross 3:
For the trait red green the recombination rate can be calculated by calculating the progeny that shows their separation i.e.
Red green recombination rate= 71+68/ 947* 100
= 139/947*100
= 14.67%
b) A map of the chromosome showing spatial relationship between the genes can be drawn by estimating the recombination values. In this case the recombination value for odd green (18.58%) is closer to the odd red+ red green= 3.14+14.67 = 17.81%. Therefore, red should be located between odd and green. This means that the map can be made as
odd--------red--------------green
3.14 14.67
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