Question

In a dihybrid cross between two heterozygotes $AaBb \times AaBb$, if we get $3 : 1$ ratio among the off springs, the reason for this may be

• A. polygenes
• B. linked genes
• C. pleiotropic genes
• D. hypostatic genes

Answer 1

Answer: (B)

linked genes

Answer 2

The genes which tend to transmit together as a single unit as they are located very close on the same chromosome from one generation to the next are called linked genes. The linked genes modify the Mendelian dihybrid ratio from $9 : 3 : 3 : 1$ to $3 : 7$ and dihybrid test ratio from $1 : 1 : 1 : 1$ to 41 : 1$. Pleiotropic genes is the interaction in which one gene produces, many effects. The gene that suppresses the other one is called epistatic and the one which is prevented from exhibiting itself is called hypostatic.