The recombination frequency between the genes a & c is $5\%$, b & c is $15\%$, b & d is $9\%$, a & b is $20\%$, c & d is $24\%$ and a & d is $29\%$. What will be the sequence of these genes on a linear chromosome?

Recombination frequency is directly proportional to map distance ($1\%=1\text{cM}$).a-c $=5$ c-b $=15$ (So a-b could be $15+5=20$ or $15-5=10$).Given a-b $=20$, so the sequence is a - c - b.b-d $=9$ (So a-d could be $20+9=29$ or $20-9=11$).Given a-d $=29$, so d must be on the far side of b.Sequence: a - c - b - d.