In a mixed infection experiment,you study two plaque phenotypes of large l⁺ versus small l^- and bumpy b⁺ versus smooth b^- .You mix small l^-b⁺ with smooth l⁺b^- and identify 50 small,smooth and 47 large,bumpy.How far apart are the genes? A)490 B)99 C)49 D)1000 E)There is not enough information to calculate the distance.

Question

Quizplus · Accepted Answer

The fact that small and smooth were found together indicates that they are located on the same chromosome and did not undergo recombination. The same applies for large and bumpy. The fact that there were 50 small, smooth plaques and 47 large, bumpy plaques indicates that there was recombination between the two pairs of genes in about 3% of the total offspring. Therefore, the distance between the two pairs of genes is 3% of the total number of offspring, which is 50+47=97. 3% of 97 is approximately 3, which divided by 2 (since recombination happened in both pairs) gives a distance of 1.5, which rounded up is 2 map units or 49 units of genetic distance.

In a Mixed Infection Experiment,you Study Two Plaque Phenotypes of Large