Which nucleoside is absent in the complement to the wild-type (WT) sequence?

• A. Deoxyadenosine
• B. Deoxycytidine
• C. Deoxyguanosine
• D. Deoxythymidine

Answer: (B)

To determine which nucleoside is absent in the complement to the wild-type (WT) sequence, it's essential to understand the relationships between nucleotides and their complementary bases in DNA.

The nucleosides that comprise DNA are:

• Deoxyadenosine (corresponding to adenine, A)

• Deoxycytidine (corresponding to cytosine, C)

• Deoxyguanosine (corresponding to guanine, G)

• Deoxythymidine (corresponding to thymine, T)

In a complementary DNA strand, adenine pairs with thymine, and guanine pairs with cytosine. Therefore, the complement of each nucleoside will include its corresponding pairing.

If we assume that the wild-type sequence contains deoxyadenosine, deoxyguanosine, and deoxythymidine, the absence of deoxycytidine in the complementary sequence would mean that wherever there is a cytosine (C) in the WT sequence, there is no corresponding deoxycytidine in the complement. This leads to the conclusion that a sequence devoid of deoxycytidine will lack the necessary pairing with guanine, resulting in an incomplete or mism