Chapter 7, Problem 1SQ

Three of the many recessive mutations in Drosophila melanogaster that affect body color, wing shape, or bristle morphology are black (b) body versus grey in wild type, dumpy (dp), obliquely truncated wings versus long wings in the male, and hooked (hk) bristles versus not hooked in the wild type.  From a cross of a dumpy female with a black and hooked male, all of the F1 were wild type for all three of the characters.  The testcross of an F1 female with a dumpy, black, hooked male gave the following results:   Trait Number of individuals Wild type 169 Black 19 Black, hooked 301 Dumpy, hooked 21 Hooked, dumpy, black 172 Dumpy, black 6 Dumpy 305 Hooked 8   Determine the order of the genes and the mapping distance between genes. Determine the coefficient of confidence for the portion of the chromosome involved in the cross. How much interference takes place in the cross?

What happens to a microbes membrane at colder temperature?

Genes at loci f, m, and w are linked, but their order is unknown.  The F1 heterozygotes from a cross of FFMMWW x ffmmww are test crossed.  The most frequent phenotypes in the test cross progeny will be FMW and fmw regardless of what the gene order turns out to be.  What classes of testcross progeny (phenotypes) would be least frequent if locus m is in the middle? What classes would be least frequent if locus f is in the middle? What classes would be least frequent if locus w is in the middle?