Question

Which of the following factor was used by Alfred Sturtevant to measure the distance between the genes and mapped their position on the chromosome?

• A. Total recombination
• B. Frequency of recombination
• C. Parental gene combination
• D. Nonparental combination

Answer 1

The correct option is B Frequency of recombination

One of Sturtevant's principal contributions was his introduction to the concept that the frequency of crossing-over between two genes could help determine their proximity on a linear genetic map. His experiments determined that the frequency of double crossing over can be used to deduce gene order. He demonstrated this concept by constructing crosses of three segregating genes, called "three-factor crosses". He found that using three genes as opposed to two provided most accurate information about gene order on chromosome. With this system, Sturtevant discovered that double crossing-over occurs at frequency of equal to or less than product of two single crossing over frequencies. He also surmised that unequal crossing-over was possibly a main force of evolution.

So, the correct answer is 'Frequency of recombination'.