Domestic dogs evolved from ancestral grey wolves. Wolves have coats of short, straight hair and lack “fur-nishings,” a growth pattern marked by eyebrows and a mustache found in some domestic dogs. In domestic dogs, coat variation is controlled by allelic variation in three genes. Recessive mutant alleles in the FGF5 gene result in long hair, while dogs carrying the dominant ancestral allele have short hair. Likewise, recessive mutant alleles in the KRT71 gene result in curly hair, whereas dogs with an ancestral dominant allele have straight hair. Dominant mutant alleles in the RSPO2 gene cause the presence of furnishings, while dogs homozygous for the ancestral recessive allele have no furnishings.
A pure-breeding curly-and long-haired poodle with furnishings was crossed to a pure-breeding short-and straight-haired border collie lacking furnishings.
a. What are the genotypes and
b. If dogs of the
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Suppose a geneticist is using a three-point test cross to map three linked rabbit morphology and behavioral mutations called si, sf, and H. The gene si is associated with the silky fur phenotype, and sf is associated with the short-footed phenotype. Both si and sf are recessive mutations with respect to wild type. H is a dominant mutation that confers the hyper phenotype. The geneticist first crosses true-breeding hyper rabbits to true-breeding silky fur, short-footed rabbits. Next, the geneticist backcrosses the F₁ progeny to the silky fur, short-footed parents, and obtains the results reported in the table. Phenotype hyper silky fur, short-footed short-footed silky fur, hyper silky fur short-footed, hyper silky fur, short-footed, hyper wild type Place the genes in the correct order in the chromosome. LLIIN HEL H Number 815 807 175 169 4 5 27 29 Answer Bank si sfarrow_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! Review the information on Labrador retrievers above. What are the phenotypic ratios of the F1 generation offspring of two dihybrids? Make sure to match the numbers with coat colors (e.g, which number in the ration goes with which color). Use a Punnett square to…arrow_forwardIn mice, gene A is epistatic to gene B. Dominant allele "A" allows for pigment to be transported to the fur; recessive allele "a" prevents the transport of pigment to the fur, resulting in an albino mouse. Dominant allele "B" gives agouti fur color; recessive allele "b" gives black fur color. What phenotype would you expect from a mouse with "aaBb" genotype? * A.black and white fur B.albino fur C. agouti fur D. black furarrow_forward
- "In cattle, the allele that causes horns to grow is recessive. Another recessive allele causes the cows to grow abnormally large and muscular. These muscular cows are often called Belgian blue cows. If a cow that is heterozygous for both the horn and Belgian blue trait genes passes on the allele for growing horns to an offspring, what are the odds that the parent cow also passes on the allele for becoming very muscular to that offspring?" I know the answer is 50% but how do I get to this answer?arrow_forwardHairlessness in dogs is inherent in a single dominant allele. Inheriting two dominant alleles is lethal for an embryo. Penelope, a hairless dog mates with Arnold, a hairless dog. The probability that Penelope has hairless puppies isarrow_forwardSuppose we define the Alzheimer's disease phenotype as being diagnosed with the disease by age 75 years. In the human population, there are three alleles of the ApoE gene: e2, e3, e4. They form an allelic series such that: 70% of 75 year olds with the e4/e4 genotype have the Alzheimer's phenotype 60% of 75 year olds with the e3/e4 genotype have the Alzheimer's phenotype 40% of 75 year olds with the e3/e3 genotype have the Alzheimer's phenotype 30% of 75 year olds with the e2/e4 genotype have the Alzheimer's phenotype 10% of 75 year olds with the e2/e3 genotype have the Alzheimer's phenotype If I have the e4/e4 genotype and my wife has the e2/e3 genotype, what is the probability that our child will have Alzheimer's by age 75. Explain your reasoning.arrow_forward
- Hummingbirds have brightly colored feathers on their throats that are used to attract mates. Let's say these feathers come in three different colors red (R), yellow (Y) and grey (g). The red and yellow alleles are codominant when present together, and both red and yellow are dominant when paired with the recessive grey allele. (Hint - this is the same as the ABO blood groups in humans and, is not sex-linked). please show your work. a. A grey female mates with a yellow throated male and she lays 4 eggs. All of the resulting chicks have yellow-colored throats. What is the genotype of the male that fathered the chicks? b. The next year one of the female chicks from the nest above grows up and mates with a male that has both red and yellow feathers. What will be the genotypes and phenotypes of their offspring, and in what proportion? Assume 4 young.arrow_forwardThe bison herd on Konza Prairie has begun to show a genetic defect. Some of the males have a condition known as "rabbit hock" in which the knee of the back leg is malformed slightly. This condition is controlled by a sex-linked gene and it is recessive. Now, suppose that the herd bull (the dominant one which does most of the breeding) who is normal (XN) mates with a cow that is a carrier for rabbit hock. What are his chances of producing a normal son (bull)? If he mates with this cow every year, what percentage of their daughters will have normal knees? What percentage of their daughters will be carriers of rabbit hock?arrow_forwardGlobal warming is causing more and more ice to melt each year at far-northern latitudes, exposing more bare ground than ever before. These vast areas of brown ground coloration make polar bears (which are white) much more conspicuous to their prey. Recently, an infant polar bear was born with brown fur. This polar bear survived to adulthood and has sired several offspring with brown fur. Which of the following is a plausible explanation of how the brown fur trait appeared in these polar bears? (a) A polar bear realized it would be better to be brown in order to hide more effectively. It induced mutations to occur in its fur pigment gene, which resulted in a change in pigment from white to brown fur. (b) One or more random mutations occurred in the fur pigment gene in an individual polar bear embryo, which resulted in a change in pigment from white to brown fur. (c) Increased temperatures due to global warming caused targeted mutations in the fur pigment gene in an individual polar bear…arrow_forward
- Two hedgehog parents are heterozygous at the spiny locus, each with genotype Ss. This locus affects the length of the individuals’ spines, which ranges from 1 cm in SS homozygotes to 3 cm in ss homozygotes.Inheritance of spine length in this family is entirely due to the spiny locus and it exhibits additivity. Remember that development of spines depends on thousands of genes, but we’re only considering this one gene because it’s the one that varies in a way that affects spine length in this family. a) List all of the phenotypes we could observe among offspring of these Ss heterozygote parents. b) What’s the probability that an offspring of these heterozygous parents is an SS homozygote? c) If the parents have exactly two offspring, what is the probability that the two hedgehog kids have no alleles in common? In other words, what’s the probability that one kid is SS and the other ss?arrow_forwardSuppose we define the Alzheimer’s disease phenotype as being diagnosed with the disease by age 75 years. In the human population, there are three alleles of the ApoE gene: ε2, ε3, ε4. They form an allelic series such that: 70% of 75 year olds with the ε4/ ε4 genotype have the Alzheimer’s phenotype 60% of 75 year olds with the ε3/ ε4 genotype have the Alzheimer’s phenotype 40% of 75 year olds with the ε3/ ε3 genotype have the Alzheimer’s phenotype 30% of 75 year olds with the ε2/ ε4 genotype have the Alzheimer’s phenotype 10% of 75 year olds with the ε2/ ε3 genotype have the Alzheimer’s phenotype If I have the ε4/ ε4 genotype and my wife has the ε2/ ε3 genotype, what is the probability that our child will have Alzheimer’s by age 75. Explain your reasoning. [Can be answered in less than 75 words]arrow_forwardWhite throated sparrows have been called 'the bird with four sexes' because of their supergene. Within white throated sparrows there is 'disassortative mating' for alleles at this super gene - every breeding pair has one individual who has a tan throat, and one individual with a white throat (Tuttle et al. 2016, Current Biology, http://dx.doi.org/10.1016/j.cub.2015.11.069). Tan striped sparrows are homozygous whereas white striped sparrows are heterozygous. From this, we conclude which of the following about the super gene: White throat homozygotes could be inviable Tan alleles are haploinsufficent White alleles are 'poisonous' Multiple genes in the super gene are interactingarrow_forward
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