In salamanders, green skin (G) is dominant yellow skin (g), a detachable tail (D) is dominant over a non-detachable tail (d), and black eyes (B) are dominant over red eyes (b). The following cross is performed between two salamanders: GgDdBb x ggDdBb On your own paper, draw a forked-line diagram for this cross and clearly show the expected phenotypic proportions (fractions) of the offspring.

The following results were obtained from a dihybrid cross between two pea plants:   315 plants with round seeds and yellow flowers 101 plants with wrinkled seeds and yellow flowers 108 plants with round seeds and white flowers 32 plants with wrinkled seeds and white flowers   Assume that round seeds and yellow flowers are dominant and both parent plants were heterozygous for both traits.

A cross was performed using Drosophila melanogaster involving a female known to be heterozygous for both ebony body and sepia eyes and a male known to be homozygous wild type male. The resulting progeny were allowed to mate with one another to produce the data set. Three repetitions of the experiment were conducted. The following data were produced from the crosses. Test these data to determine if they are significantly different from the expected phenotypic ratio. Use the 5% level of significance.  Your answer should include the hypothesized cross in genotypes, the Chi-squared value, the critical value and whether you reject or do not reject for each experiment. Wild eye Wild body – 112, Wild eye Ebony body – 40, Sepia eye Wild body – 35, Sepia eye Ebony body – 11

In the red spotted butterfly there are two traits under investigation.  The wing margin can be either notched (N) or straight (n) and the wing color can be either pale yellow (b) or bright yellow (B).  A bright yellow male with straight wing margins was crossed with a bright yellow female with notched wing margins.  All of the resulting progeny had notched wings and both color patterns were present.  From these data determine the genotypes of the butterflies used in the original cross.

A presumed dihybrid in Drosophila, BbFf is testcrossed with bbff. (B-black body, b-brown body, F-forked bristles, f-unforked bristles) The results for the testcross are below: Black, forked: 230  Black, unforked: 210 Brown, forked: 240 Brown, unforked: 250 Determine the expected values and ratios for each genotype.