Concept explainers
A planet is inhabited by creatures that reproduce with the same hereditary patterns seen in humans. Three
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Campbell Biology: Australian And New Zealand Edition + Mastering Biology With Etext
- In cattle, the gene for hornless (H) is dominant to the gene for horned (h), the gene for black (B) is dominant to that of red (b), and the gene for white face, or Hereford spotting, (S) is dominant to that for solid color (s). A cow (female) that is heterozygous for all traits is inseminated by a bull (male) of the genotype bbhhSs. What is the probability of obtaining a calf that is a black, hornless bull with Hereford spotting?arrow_forwardDr. Disney has been raising exotic fruit flies for decades. Recently, he discovered a strain of fruit flies that in the recessive condition have baby blue eyes that he designates as bb. He also has another strain of fruit flies that in the recessive condition have pink wings that are designated as pw. He is able to establish flies that are homozygous for both mutant traits.He mates these two strains with each other. Dr. Disney then takes phenotypically wild- type females from this cross and mates them with double recessive males. In the resulting testcross progeny, he observes 500 flies that are of the following makeup:41 with baby blue eyes and pink wings207 with baby blue eyes only210 with pink wings only42 with wild-type phenotype14. Assuming the wild-type alleles for these two genes are b+ and pw+, what is the correct testcross of the F1 flies?A) b+ pw+/b pw ⋅ b pw/b pwB) b+ pw+/b pw ⋅ b pw+/b+ pwC) b+ pw/b pw+ ⋅ b pw/b pwD) b+ pw/b pw+ ⋅ b+ pw+/b pwE) b+ pw+/b pw ⋅ b+ pw/b…arrow_forwardTwo pea plants that are true-breeding for recessive white flowers are mated and their offspring analyzed. Which of the following statements about this situation is true? Group of answer choices A)The offspring represent the P generation. B)The gametes produced by the offspring will carry only one allele for this gene. C)Both parents are referred to as heterozygotes. D)Half of the offspring will be true-breeding for white flowers.arrow_forward
- In the world of Weeping angels, those with pointy wings are (A_), while those with round wings are (aa). In the efforts to explore this extraordinary species, you wish to determine the genotype of a pointy winged angel. Luckily, you have trapped a round winged angel that you can cross your pointy winged angel with. If the pointy winged angel is homozygous what phenotypic ratio do you expect from their offspring? (Pointy wing: round wing) Group of answer choices a. 1:0 b. 2:1 c. 1:1 d. 3:1arrow_forwardAlbinism is caused by an autosomal recessive allele that interferes with skin pigmentation in mammals. Two normally pigmented human parents already have an albino boy. They plan to continue to have children until they get a girl. Some or all of this information is important for each of the questions below. a) What is the probability that their next child (currently unborn) will be a girl with albinism? Explain your reasoning. b) What is the probability their first female child will be albino? Explain your reasoning. c) The answer to part (b) is different (and, yes, the answer is different) from the answer to part (a). Explain why. (Hint: it has something to do with the underlined words.)arrow_forwardSex determination in birds is different from that in humans. The sex chromosomes in birds are called Z and W, because males have two of the same chromosome (ZZ), whereas females have two different chromosomes (ZW). There is a Z-linked allele in some birds that causes the death of the embryo when the normal dominant allele is not present. What would be the sex ratio in the living offspring of a cross between a male heterozygous for the lethal allele and a normal female? A) What are the genotypes of the parents? Male____ Female____ B) Which gametes would each form? Male____ Female____ C) Draw your Punnett square below and determine the sex ratios of living offspring.arrow_forward
- There are two genetically-determined traits that are seen in a species of salamander. The S-gene codes for spotting: SS or Ss = white spots; ss = no spots. The W-gene codes for skin texture: WW or Ww=wrinkly; ww = smooth. If a cross is done between SSWW and ssww parents, what genotype(s) would you expect to see in the offspring of this dihybrid cross? NOTE: Assume no recombination. O Ss, ss, WW. ww O SW, sw, Sw, sw O SsWw O SSWW, sswwarrow_forwardA species of fish can either have dominant red tins (R) or recessive white fins (r). Fin lengths can either be dominant long (L) or recessive short (1). A dihybrid cross between two of these fish occurs. Each fish is heterozygous for the traits of fin color and fin length. How many possible gamete genotypes will each parent fish produce? A-1 B-4 C-2 D-3arrow_forwardSemen from a promising bull is going to be used for artificial insemination. However, the owner is concern that the bull may carry a recessive lethal condition. Cows in the heard are 35% homozygous dominant and 65% are heterozygous for the lethal gene. Using these information calculate the number of cows that the owner has to inseminate in order to be 90% confident that the bull is not a carrier. (Assume that all cows inseminated will have healthy normal calves).arrow_forward
- Tay-Sachs is a recessive lethal disease in which there is neurological deterioration early in life. This disease is rare in the population overall but is found at relatively high frequency in Ashkenazi Jews from Eastern Europe. A woman has a maternal uncle who had the disease. Her father does not come from a high-risk population. Her husband’s sister died of the disease at an early age. Draw the pedigree of the individuals described. Include the genotypes where possible.arrow_forwardIn the video game Animal Crossing: New Horizons, flowering breeding is based in genetics. Each flower's color is determined by the genotype at three or four unlinked genes: R, Y, W, and S. The genotype of the elusive blue rose is RR YY ww ss. In the game, one way to get a blue rose is to cross two roses with the Rr Yy Ww ss genotype. A) What types of gametes and in what proportions will a Rr Yy Ww ss rose produce? B) In a cross Rr Yy Ww ss x Rr Yy Ww ss what are the possible offspring genotypes and at what frequency will they each appear? Show your work. C) What proportion of the offspring of the cross will be blue roses?arrow_forwardAs seen in the photo, Labradors come in three colors-- black, brown and yellow. What is the genetic basis for these different coat colors? One gene produces melanin, a pigment which is deposited in the dog's fur and makes the color dark. With this gene, allele B (black) is dominant to allele b. Only in the case of a recessive homozygote (bb) will the dog's phenotype be brown. The regulatory gene is separate from the melanin gene but it acts as a switch, either turning the melanin gene on or turning it off. Allele E is dominant and allows for the melanin to be deposited in the dog's fur ("on" switch), but if the switch gene is a recessive homozygote, the melanin is blocked ("off" switch) and a yellow dog is the result! 1. Two other Labradors mate and produce puppies. Their genotypes are Bbee and BbEe. What color are each parent and what are the phenotypic rations of their offspring in the F1 Generation? Show your work with a Punnett square.arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning