In 1913, Alfred Sturtevant published the first genetic map, a linear arrangement
ID: 161888 • Letter: I
Question
In 1913, Alfred Sturtevant published the first genetic map, a linear arrangement of five genes on the Drosophila melanogaster X chromosome. Of the five genes he mapped, yellow (y) affected body color, white (w) and vermillion (v) affected eye color, and rudimentary (r) and miniature (m) affected wing shape. Below are summaries of two-factor linkage data used by Sturtevant (1913, J. Exp. Zool. 14:43-59) to derive the first linkage map of the Drosophila melanogaster X chromosome. What is the order of these genes on the X chromosome? y-w-v-r-m w-y-r-v-m w-m-r-v-y r-m-y-v-w v-r-y-w-m Among the experiments listed in Sturtevant's paper was a cross between a white-eyed, miniature-winged female and a wild-type male. All of the F_1 females were wild type, whereas all of the F_1 males had white eyes and miniature wings. In the F_2 generation there were 395 wild-type flies, 223 flies with white eyes, 247 with miniature wings and 382 with white eyes and miniature wrings. What is the observed recombination frequency between white and miniature? 0.179 0.198 0.306 0.317 0.377 0.623 What is the genetic map distance, corrected using the Kosambi function, between the two genes? 18.7 cM 21.3 cM 35.6 cM 49.1 cM 98.2 cMExplanation / Answer
8)the order of genes on X chromosome is:E)V-R-Y-W-M
9)recombinant frequency-247/382=>0.623 so the answer is F)0..623
10.The genetic map distance is 214-115=>E)98.2cm approx