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When true-breeding mice with brown fur and short tails
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Genetics: Analysis and Principles
- Please label the tetrad type in the table as PD (parental ditype), NPD (non parental ditype) or T (tetratype) and answer the following questions a) Are the genes linked? Please explain SPECIFICALLY how you can distinguish between linked and unlinked genes in this instance. b) If the two genes are linked, calculate the % recombination between ser and thr. Show the formula used, as well as all of your calculations. c) Draw a single map illustrating the arrangement of the two genes on the chromosome with respect to each other and to the centromere of the chromosome. Make sure to map ALL three distancesarrow_forwardIn a cross between a white-eyed female (ww) and a red-eyed male (w+Y), nearly all the progeny were either red-eyed females (w+w) or white-eyed males (wY). However, about 1 in every 2000 F1 flies had an "exceptional phenotype" and was either a white-eyed female or red-eyed male. How did Bridges explain this unexpected result? A) Crossing over B) Incomplete cytokinesis C) Incorrect synapsis D) Nondisjunction E) Pseudoautosomal regionarrow_forwardA cross in Drosophila melanogaster involved the recessive X-linked genes for white eye (w), yellow body (y), and cut wings (c). A wild-type tri-hybrid female was crossed with wild-type males and only the male offspring were tallied. On the basis of the results shown below, which of the choices shown best represents the genetic map of the three loci on the X-chromosome? Phenotype Male Offspring + у t 494 394 + + ct 28 w y + 35 + у + 105 w + ct 101 w y ct 5 5.4 mu 17.6 mu ct 6.1 mu 18.3 mu w ct 17.6 mu 5.4 mu ct 18.3 mu 6.1 mu ct 6.1 mu 18.3 mu ct Submit Request Answer de Feedback Next >arrow_forward
- In a testcross of a female Drosophila heterozygous for 3 linked, recessive genes the following phenotypes were observed and used to make a map of these genes. Calculate the interference. A---(3.0)---D-----(4.8)-----B A) There is negative interference. B) 1.44 C) 2.08 D) 1 E) 0arrow_forwardA cross in Drosophila melanogaster involved the recessive X-linked genes for white eye (w), yellow body (y), and cut wings (c). A wild-type tri-hybrid female was crossed with wild-type males and only the male offspring were tallied. On the basis of the results shown below, which of the choices shown best represents the genetic map of the three loci on the X-chromosome? Phenotype Male Offspring + y ct 494 w + + 394 + + ct 28 w y + 35 + y + 105 w + ct 101 w y ct 5 + + + 3arrow_forwardMultiple crosses were made between true-breeding lines of black and yellow Labrador retrievers. All the F1 progeny were yellow. When these progeny were intercrossed, they produced an F2 consisting of 121 yellow, 9 black and 30 chocolate. What epistatic ratio and what kind of epistasis is approximated in the F2? Propose a biochemical pathway for coat color in Labrador retrievers based on the type of epistasis. Correlate each genotype with the phenotype that would occur in your pathway. Also show the frequency of each genotype. A-B- A-bb aaB- aabbarrow_forward
- Females of wild-type Strain A and males of mutant Strain B, as well as females of mutant Strain B and males of wild-type Strain A, make reciprocal crosses. Explain why reciprocal crosses are needed in genetics experiments involving Drosophila fruit flies.arrow_forward1) Imagine you discover a new mutant strain of tailless mice. Upon looking closer, you notice that I is only the females who are tailless. In paired matings with tailless females crossed with normalmales, you find that the progeny are always recovered in the following ratios: 1/3 tailless females, 1/3 normal females, 1/3 normal males. a)What is the most likely genotype of the tailless mice? b) Provide a simple explanation for the ratio: 1/3 tailless females, 1/3 normal females, 1/3 normal males.arrow_forwardIn snapdragons, red flower color (R) is incompletely dominant over white flower color (r). The hybrids or heterozygous plants (Rr) are pink in color. a) Show the genotype for a white flower and for a red flower. b) If a red-flowered plant is crossed with a white-flowered plant, what are the genotypes and phenotypes of the F1 generation plants? c) What genotypes and phenotypes will be produced in the F2 generation? d) How did the genotypic and phenotypic ratio compare to each other in this incomplete dominance cross? e) What would the phenotypic ratio have been if this had been complete dominance? f) What kind of offspring can be produced if a red-flowered plant is crossed with a pink-flowered plant? g) What kind of offspring is/are produced if a pink-flowered plant is crossed with a white-flowered plant?arrow_forward
- The A locus and the D locus are so tightly linked that norecombination is ever observed between them. If Ad/Ad is crossed with aD/aD and the F1 is intercrossed,what phenotypes will be seen in the F2 and in whatproportions?arrow_forwardA spotted gerbil (C) with short fur (F) is crossed with an albino gerbil (c) with long fur (f). The spotted, short-furred offspring are crossed with an albino (c) long-fur (f). A) What types of offspring and in what proportions would you expect if the two genes were unlinked? B) What would you expect if they were linked and 30 m.u. apart?arrow_forwardIndividuals of genotype AaBb were mated to individuals of genotype aabb. One thousand offspring were counted, with the following results: 474 Aabb, 480 aaBb, 20 AaBb, and 26 aabb. What type of cross is it? Are these locilinked? What are the two parental classes and the two recombinant classes of offspring? What is the percentage of recombination between these two loci? How many map units apart are they?arrow_forward
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