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There are now nearly 200 recognized breeds of dog, from the affenpinscher to the Yorkshire terrier. But several of these suffer from medical problems due to the inbreeding required to establish the breed. For example, nearly every Cavalier King Charles Spaniel (discussed in the Biology and Society section) suffers from heart murmurs caused by a genetically defective heart valve. Such problems are likely to remain as long as the organizations that oversee dog breeding maintain strict pedigree requirements. Some people are suggesting that every breed be allowed to mix with others to help introduce new gene lines free of the congenital defects. Why do you think the governing societies are resistant to such crossbreed mixing? What would you do if you were in charge of addressing the genetic defects that currently plague some breeds?
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- Dr. 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_forwardCertainly, not all Muppets look like the one shown in the picture below, nor do they all look the same. In fact, there’s a great deal of phenotypic variation in Muppets. Two traits that have been particularly well-studied are curly hair presences and skin color. One individual is a male, and he possesses a green skin and no hair, whereas the female individual possess a curly hair and pink skin. Let’s call the gene controlling skin coloration S and that controlling hair H. In this species, both hair and green skin are recessive traits. Both of the individuals shown are homozygous. 1. What is the genotypes of Miss Piggy: 2. Kermit's Genotype: 3. If these two lovebirds (er, love-muppets?) mated, what would their offspring look like? Describe all phenotype combinations possible and the ratios in which they would occur?arrow_forwardA very large population of rabbits has been allowed to breed randomly in a laboratory research program. The rabbits vary in their coat colour, which is either gray or black. After many generations, 25% of the rabbits display a recessive phenotype for gray coat colour (aa), the same percentage as at the beginning of the breeding program. The other 75% of the rabbits show the dominant black coat phenotype, with heterozygotes (Aa) indistinguishable from the homozygous dominants (AA) What is a reasonable conclusion explaining the fact that the frequency of the recessive trait (aa) has not changed over time? a. There has been sexual selection favouring allele a b. The two phenotypes have about equal fitness under laboratory conditions C. The population is undergoing genetic drift d. The genotype AA is lethalarrow_forward
- To understand this research, you must be familiar with some basic genetic terminology. Drag the terms on the left to the appropriate blanks on the right to complete the sentences. Not all terms will be used. dominant allele phenotype The possession of two different alleles of a particular gene is referred to as Reset Help A variation in a DNA sequence at one particular position is called a heterozygosity genotype recessive allele homozygosity single nucleotide polymorphism The appearance of the organism, its observable traits, are referred to as the A variant of a gene for which an individual must be homozygous in order for it to influence the appearance of the organism is a The set of alleles an organism has for a particular trait is the organism's Submit Request Answerarrow_forwardConsider two blood polymorphisms that humans have in addition to the ABO system. Two alleles LM and LN determine the M, N, and MN blood groups. The dominant allele R of a different gene causes a person to have the Rh+ (rhesus positive) phenotype, whereas the homozygote for r is Rh− (rhesus negative). Two men took a paternity dispute to court, each claiming three children to be his own. The blood groups of the men, the children, and their mother were as follows:From this evidence, can the paternity of the children be established?arrow_forwardThe zebra fish is a very popular aquarium pet fish that is known to be hardy, attractive, and able to survive well in groups. Wild type zebra fish have blue–purple horizontal stripes that run from gill to tail, with a silver–gold body. An alternative form of the zebra fish results from a mutation that causes a homozygous recessive red-colour fish. Could you kindly answer all of the questions? It's multiple choice so minimal explanation is needed and i do not have a lot of questions left. Thank you. a) If 32 of 84 zebra fish have the recessive phenotype of red colour, what is the frequency of the recessive allele in this population of fish? a. 0.62 b. 0.38 c. 0.14 d. 0.79 b) What percentage of the population of zebra fish are heterozygous? a. 47% b. 38% c. 62% d. 53% c)How many zebra fish are purebreeding for the blue–purple horizontal stripes? a. 72 b. 12 c. 52 d. 5 d) If 15 years ago, 34 of 88 zebra fish had the red colour, has microevolution occurred? Why or why not?…arrow_forward
- Examples of codominance include ABO blood type and coat color in cattle. In short horn cattle coat color pattern is determined by two alleles (CR = red; CW = white) that are both equally expressed. CRCW cattle are roan (red and white patches); therefore, both alleles affect the phenotype equally. The ABO system of blood typing exhibits codominance in humans. There are 3 alleles for the gene that determine ABO blood type (IA and IB are codominant alleles; allelei is recessive to alleles IA and IB). IAIA and I^i are type A; I®I® and IPi are type B; I^IB is type AB; ii is type O Practice Problem 4: 4a. If a man with blood type O marries a woman that is blood type AB, what are the predicted genotypes and phenotypes of their children? 4b. If a man with blood type A (I^i) marries a woman with blood type AB, what are the predicted genotypes and phenotypes of their children?arrow_forwardWhat is meant by the term ‘breed’? What are the objectives of animalbreeding?arrow_forwardIn this program, you are provided with phenotype pair counts of F2 offspring at two research institutes. The key different between this work and previous work is that now we consider two genes instead of one. The phenotype pairs are the (shape, color) of peas from a pea plant. It turns out that there are two separate genes that code for these phenotypes. We shall call them Shape and Color. Gregor Mendel originally recorded these experiments in green peas. Using the notation: R = Round (dominant) allele at Shape gene; r = Wrinkled (recessive) allele at Shape gene; Y = Yellow (dominant) allele at Color gene; y = Green (recessive) allele at Color gene; then the shape and color of any pea can be determined by studying the genotypes at each gene. It turns out that, when one mates a plant that is homozygous for the dominant alleles (RRYY) with a plant that is homozygous for the recessive alleles (rryy), the F1 generation are heterozygous at both genes, as with a single gene disorder.…arrow_forward
- Albinism is a recessive trait in humans. A geneticist studies families in which both parents are normal and at least one child has albinism. The geneticist reasons that both parents in these families must be heterozygous and the albinism should appear in 1⁄4 of the children of these families. To his surprise, the geneticist finds the frequency of albinism trait is quite high. As a consultant, can you suggest an explanation for the higher expected frequency of albinisms in these families?arrow_forwardThe population risk of NIDDM is highly dependent on the population under consideration; in most populations, this risk is 1%-5%, although it is 6% to 7% in the United States. If a patient has one affected sibling, the risk increases to 10%; an affected sibling and another first-degree relative, the risk is 20%; an affected monozygotic twin, the risk is 50%-100%. 1) Is this a single gene inheritance or multifactorial disease? 2) Is there a strong genetic or environmental cause to the development of this disease? If both genetic and environmental causes are implicated, you have to indicate each of them separately.arrow_forwardTay-Sachs disease is a recessive genetic disease. Individuals with this disease rarely survive past the age of four. In the general population, approximately 1 person in 300 carries the allele for this disease. However, in some populations, including the Irish Americans, the Ashkenazi Jews, and the Cajuns from Louisiana, the proportion of Tay-Sachs carriers is much higher (1 in 27 to 1 in 50) than in other populations. Such high frequency of an otherwise rare allele is expected when Question 24 options: populations experienced disruptive selection populations were founded by a small number of settlers the allele is advantageous at the heterozygous state populations have higher than average mutation rates populations experienced stabilizing selectionarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning