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4. In mice, the genes for gray hair (G) and a long tail (L) are dominant over white hair (g) and a short tail (I). These genes are syntenic and linked. A female gray mouse with a long tail is heterozygous for both genes, and is mated to a white mouse with a short tail. Over the course of a year they produce many offspring, with the phenotypes described in the table below. Offspring phenotype Gray, long tail Gray, short tail White, long tail White, short tail # of Offspring 6 24 26 4 a) What gametes can the female mouse produce? Offspring Genotype b) Combine mom's gametes with dad's gametes and fill in the genotypes in the correct location in the table. c) Which offspring are parental, and which are recombinant? How can you tell?
d) Based on your answer to part c, draw "mom's" original two chromosomes, showing which alleles are on each. e) Calculate the recombination frequency and draw the map of these two genes on a chromosome.
1. Researchers cross a corn plant that is pure-breeding for the dominant traits colored aleurone (C1), full kernel (Sh), and waxy endosperm (Wx) to a pure-breeding plant with the recessive traits colorless aleurone (c1), shrunken kernel (sh), and starchy endosperm (wx). The resulting F1 plants were crossed to pure-breeding colorless, shrunken, starchy plants. Counting the kernels (offspring) from about 30 ears of corn yields the following data: Kernel Phenotype Colored, shrunken, starchy Colored, full, starchy Colored, full, waxy Colored, shrunken, waxy Colorless, shrunken, starchy Colorless, full, starchy Colorless, full, waxy Colorless, shrunken, waxy Number 116 601 2538 4 2708 2 113 626 6708
a. Which of these offspring are considered parental? How do you know? b. Which gene is in the middle? How can you tell? c. Calculate the recombination frequencies between the gene pairs (for SCO-1 and SCO-2). Make sure you identify which gene pair (ex: Sh-Wx or Sh-C1, etc) you are referring to in each case. e. What is the interference value for this data set?