4. In cattle, polled (absence of horns) is dominant over horned and roan is the result of the heterozygous condition of the genes for red and white coat color. (Neither red nor white is dominant so in the heterozygote, both are expressed.) Assume both traits are on separate pairs of autosomes. What proportion of the offspring of a roan heterozygous polled bull and a roan horned cow would be expected to be roan and horned?

4. In cattle, polled (absence of horns) is dominant over horned and roan is the result of the heterozygous condition of the genes for red and white coat color. (Neither red nor white is dominant so in the heterozygote, both are expressed.) Assume both traits are on separate pairs of autosomes. What proportion of the offspring of a roan heterozygous polled bull and a roan horned cow would be expected to be roan and horned?

Biology: The Dynamic Science (MindTap Course List)

4th Edition

ISBN:9781305389892

Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Publisher:Peter J. Russell, Paul E. Hertz, Beverly McMillan

Chapter13: Genes, Chromosomes, And Human Genetics

Section: Chapter Questions

Problem 8TYK: Another gene in Drosophila determines wing length. The dominant wild-type allele of this gene...

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. The normal eye color of Drosophila is red, but strains inwhich all flies have brown eyes are available. Similarly,wings are normally long, but there are strains with shortwings. A female from a pure line with brown eyes andshort wings is crossed with a male from a normal pureline. The F1 consists of normal females and short-wingedmales. An F2 is then produced by intercrossing the F1.Both sexes of F2 flies show phenotypes as follows:38 red eyes, long wings38 red eyes, short wings18 brown eyes, long wings18 brown eyes, short wingsDeduce the inheritance of these phenotypes; useclearly defined genetic symbols of your own invention.State the genotypes of all three generations and thegenotypic proportions of the F1 and F2.Unpacking Problem 31Before attempting a solution to this problem, try answering thefollowing questions:1. What does the word normal mean in this problem?2. The words line and strain are used in this problem.What do they mean, and are they interchangeable?3. Draw a simple…
1. The lubber grasshopper is a very large grasshopper and is black with red and yellow stripes. The alleles for red and yellow stripes are co-dominant. Assume that red stripes are expressed from the homozygous RR genotype, yellow stripes from the homozygous YY genotype, and both from the heterozygous genotype RY. a. How many of each genotype will be found in the F1 generation resulting from a cross of two grasshoppers, both with red and yellow stripes? b. How many of each phenotype?
2. a. A Drosophila male from a true-breeding stockwith scabrous eyes was mated with a female from atrue-breeding stock with javelin bristles. Both scabrous eyes and javelin bristles are autosomal recessive mutant traits. The F1 progeny all had normaleyes and bristles. F1 females from this cross weremated with males with both scabrous eyes andjavelin bristles. Write all the possible phenotypicclasses of the progeny that could be produced from the cross of the F1 females with the scabrous, javelin males, and indicate for each class whether it is arecombinant or parental type.b. The cross in part (a) yielded the following progeny:77 scabrous eyes and normal bristles; 76 wild type(normal eyes and bristles); 74 normal eyes andjavelin bristles; and 73 scabrous eyes and javelinbristles. Are the genes governing these traits likelyto be linked, or do they instead assort independently? Why?c. Suppose you mated the F1 females from the crossin part (a) to wild-type males. Why would thiscross fail…
17. In rats, the following genotypes of two independently assorting autosomal genes determine coat color.A_B_ (gray)A_bb (yellow)aaB_ (black)aabb (cream)A third gene pair on a separate autosome determines whether or not any color will be produced.The CC and Cc genotypes allow color according to the expression of the A and B alleles.However, the cc genotype results in albino rats regardless of the A and B alleles present. Given the inheritance pattern of coat color in rats described in Problem 17, predict the genotype and phenotype of the parents who produced the following offspring: (c) 27/64 gray: 16/64 albino: 9/64 yellow: 9/64 black: 3/64 cream
2. In Drosophila, gray body color is dominant to ebony body color, while long wings are dominant to vestigial wings. Assuming that the F1 individuals are homozygous, work the following crosses through the F2 generation, and determine the genotypic and phenotypic ratios for each generation. (a) gray, long × ebony, vestigial
5 f There are two genes that determine the coat colour expression in dogs: eumelanin and merle. These genes are located on two separate chromosomes. For the eumelanin gene, black coat colour (E) is dominant over red coat colour (e). The merle gene controls the degree to which these coat colours are expressed through incomplete dominance. The following table describes the merle gene expression. Genotype MM Mm mm Phenotype White AAY Half colour (Grey or light red) Full colour (Black or Red) 1. If a dog breeder wants to determine the unknown genotype of a dog, what colour of dog must she use as a testcross? 2. A white dog was testcrossed, and all of the puppies had light red coats. What is the genotype of the white dog? Use a Punnett square to show your work. Hint - When a trait is controlled by two genes, an individual's genotype consists of 4 letters. = = = B I 123 ||| 14 E E I ос C GO * ●● ● ●0 00 00 00 ✓ C U up X₂ x²
3. Two Drosophila flies that had normal (transparent, long) wings were mated. In the progeny, two new phenotypes appeared, dusky wings (having a semi-opaque appearance) and clipped wings (with squared ends). The progeny were as follows: Females: Males: 179 transparent, long 58 transparent, clipped 92 transparent, long 89 dusky, long 28 transparent, clipped 31 dusky, clipped a) Provide a genetic explanation for these results, showing genotypes of parents and of all progeny classes under your model. b) Design a test for your model.
1.In Drosophila melanogaster body color is controlled by one gene while wing shape is controlled by a second gene. Gray body color is dominant to black body color, and normal wings are dominant to vestigial wings. Flies homozygous for gray body color and vestigial wings are crossed with flies homozygous for black body color and normal wings. A.compare the possible f2 generation genotypes and phenotypes and proportions if these two traits. B.How does your answer change if one of the original parents is homozygous for gray body color and normal wings while the other has black body color and vestigial wings?
4. In Drosophila melanogaster, a yellow-bodied (dark coloured) male with vestigial (underformed) wings is crossed to a wildtype female (brown body, red eyes). The F1 generation are all wildtypes. An F1 male and female are crossed and the F2 progeny consists of 16 vestigial-winged males with yellow bodies, 48 yellow males with normal wings, 15 males with vestigial wings and yellow bodies, 49 wildtype males, 31 vestigial winged females with brown bodies and 97 wildtype females. Explain the inheritance pattern of the 2 genes.
a. In Drosophila, crosses between F1 heterozygotes ofthe form A b / a B always yield the same ratio ofphenotypes in the F2 progeny regardless of the distance between the two genes (assuming completedominance for both autosomal genes). What is thisratio? Would this also be the case if the F1 heterozygotes were A B / a b? (Hint: Remember that inDrosophila, recombination does not take placeduring spermatogenesis.)b. If you intercrossed F1 heterozygotes of the formA b / a B in mice, the phenotypic ratio among the F2progeny would vary with the map distance betweenthe two genes. Is there a simple way to estimate themap distance based on the frequencies of the F2phenotypes, assuming rates of recombination areequal in males and females? Could you estimatemap distances in the same way if the mouse F1heterozygotes were A B / a b?
1. The allele G for yellow stigma is completely dominant to green (g). Supposingtwo strains of autotetraploid plants are available and their genotypes are as follows:GGgg – in this plant the gene is close to the centromereGggg – in this plant the gene is far from the centromere If these two plants are crossed:a) provide the gametes that can be obtained from the two plants;b) provide the genotypic and phenotypic ratios of the offspring. 2. Consider the illustration below. Diagram the configuration you would observe at Anaphase I if crossing-over happens within the inversion. (IMAGE ATTACHED)
7) In cats, the gene for coat color is both X-linked and incompletely dominant. There are black coat and yellow coat alleles, with calico (tortoise shell) as the heterozygous form. If a yellow male mates with a calico female, what are the expected offspring phenotypes (in percent)? hbit