The percentage of crossing over between a and b = 20%, a and c = 8%, b and c = 28%. The sequence of genes is
The percentage of crossing over between a and b = 20%, a and c = 8%, b and c = 28%. The sequence of genes is
The correct option is A b,a,c
Since, recombination frequency is
directly proportional to distance between genes, the values are used to locate
genes on a chromosome. Here, three genes a, b and c can assume any of three
linear sequences : a-b-c or a-c-b or b-a-c which depends of the gene present in
the middle. Here, recombination frequency for a and b (X) = 20%, that for a and
c (Y) = 8% and for b and c (Z) =28%. As we can see that Z = X + Y or 28 = 20+8
which means that genes b and c are present at extremes and a is in the middle.
Thus, the sequence of genes is b-a-c. Correct answer is B. For gene sequence a-b-c,
Y = X+Z; but it does not hold true for given values of recombination frequency
which makes option A wrong. For gene sequence a-c-b or b-c-a, X = Y + Z; but it
does not hold true for given values of recombination frequency which makes options C and D wrong.
Since, recombination frequency is directly proportional to distance between genes, the values are used to locate genes on a chromosome. Here, three genes a, b and c can assume any of three linear sequences : a-b-c or a-c-b or b-a-c which depends of the gene present in the middle. Here, recombination frequency for a and b (X) = 20%, that for a and c (Y) = 8% and for b and c (Z) =28%. As we can see that Z = X + Y or 28 = 20+8 which means that genes b and c are present at extremes and a is in the middle. Thus, the sequence of genes is b-a-c. Correct answer is B. For gene sequence a-b-c, Y = X+Z; but it does not hold true for given values of recombination frequency which makes option A wrong. For gene sequence a-c-b or b-c-a, X = Y + Z; but it does not hold true for given values of recombination frequency which makes options C and D wrong.
