Question

During bacterial transformation, DNA that enters a cell is not an intact chromosome; instead it consists of randomly generated fragments of chromosomal DNA. In a transformation where the donor DNA was from a bacterial strain that was a+ b+ c+ and the recipient was a b c, 55% of the cells that became a+ were also transformed to c+ But only 2% of the a+ cells were b+. Is gene b or c closer to gene a?

Answer 1

Answer:

Gene c is closer to a.

Explanation:

• The process by which the bacteria take up the genetic material which is foreign from the environment is called as bacterial transformation and it is a type of horizontal gene transfer.
• When during transformation there is a simultaneous transfer of two or more genes then such type of transformation called co-transformation.
• According to the question, there is co-transformation occurring for both the genes a and b as well as for a and c, however, the frequency of cotransformation of a and c is higher (55%) than a and b (2%).
• A higher frequency of co-transformation indicates that the two genes are located more closely on the chromosome and hence, are usually transferred together, thus a and c are much closer as compared to a and b.