Three linked loci are evaluated to determine the recombination frequency of the loci. To set up the test cross, an individual that is true breeding dominant for all three phenotypes is crossed with an individual that is true breeding recessive for all three phenotypes. F1 offspring are crossed with individuals that are recessive for all phenotypes. The phenotypic results are shown in the table below.   Phenotype Number of Offspring Dominant 1, Dominant 2, Dominant 3 322 Dominant 1, Dominant 2, Recessive 3 82 Recessive 1, Dominant 2, Recessive 3 5 Dominant 1, Recessive 2, Dominant 3 2 Recessive 1, Dominant 2, Dominant 3 28 Recessive 1, Recessive 2, Dominant 3 89 Recessive 1, Recessive 2, Recessive 3 312 Dominant 1, Recessive 2, Recessive 3 25   1. Which two phenotypes are parental? 2. What is the map distance between locus 1 and locus 2? 3. What is the map distance between locus 1 and locus 3? 4. What is the map distance between locus 2 and locus 3? 5. Sketch a chromosome that maps the three loci based on your map distance calculations.

Genes E, F, and D are linked in that order. The distance between D and E is 1 cM, and the distance between E and F is 0.6 cM. When the parental genotypes DdEeFf x ddeeff are crossed, which of these will be the resulting F1 recombinant genotypes? Select all that apply.      options:   ddeeFF   ddEeFf   DdEeFF   DdeeFf

Consider the pedigree below. Which of the individuals MUST be heterozygous carriers of the diseasse? I II III IV OQ 3 11-2 III-1 III-2 UI-3 III-4 III-5 IV-1 IV-2 IV-3 IV-4 IV-5

Tomato Plants In tomato plants, round fruit (R) is dominant to oval fruit (r). Pure breeding plants with red and round fruit (FFRR) were crossed to pure breeding plants with yellow and oval fruit (ffrr). The red and round F1 progeny were then testcrossed to plants that were homozygous recessive for both genes (ffrr) with the following results: Phenotypes Number of Offspring Red and round 2 255 Red and oval 290 Yellow and round 310 Yellow and oval 2 145 Compare the expected probabilities of each phenotype to the observed probabilities. Are the gene for fruit colour and the gene for fruit shape assorting independently? Explain.

In corn, the allele Pr stands for green stems, pr for purple stems. A corn plant of genotype pr/pr that has standard chromosomes is crossed with a Pr/Pr plant that is homozygous for a reciprocal translocation between chromosomes 2 and 5. The F1 is semisterile and phenotypicallyPr. A backcross with the parent with standard chromosomes gives 764 semisterile Pr, 145 semisterile pr, 186 normal Pr, and 727 normal pr. What is the map distance between the Pr locus and the translocation point?

Tomato Plants In tomato plants, round fruit (R) is dominant to oval fruit (r). Pure breeding plants with red and round fruit (FFRR) were crossed to pure breeding plants with yellow and oval fruit (ffrr). The red and round F1 progeny were then testcrossed to plants that were homozygous recessive for both genes (ffrr) with the following results: Phenotypes Number of Offspring Red and round 2 255 Red and oval 290 Yellow and round 310 Yellow and oval 2 145   Convert the expected phenotypic ratio from Part A into the expected probability for each of the four phenotypes and record them in the table below. Calculate the probability for each of the four phenotypes observed in the cross from the data presented at the beginning of the question by dividing the number of progeny in each class by the total number of progeny and record these in the table below. Compare the expected probabilities of each phenotype to the observed probabilities. Are the gene for fruit colour and…

You are studying three linked genes in snapdragons. The flower color locus is in the center. There are 12.7 cM between the flower color locus and the plant height locus. There are 8.8 cM between the flower color locus and the leaf type locus. The coefficient of coincidence is 0.8. Pure-breeding tall, red-flowered plants with fuzzy leaves were crossed to pure-breeding dwarf, blue-flowered plants with smooth leaves. The F1 were testcrossed. Calculate the proportion of the testcross progeny that are expected to have blue flowers and smooth leaves. Round properly to 4 decimal digits. Answer

When true-breeding mice with brown fur and short tails (BBtt) were crossed to true-breeding mice with white fur and long tails (bbTT), all the F1 offspring had brown fur and long tails. The F1 offspring were then crossed to mice with white fur and short tails (bbtt). The fur gene and the tail length gene are 7 cM apart. Part a Which of the following F2 offspring are recombinant?  (Select all that apply.) a) White fur, short tail b) Brown fur, long tail c) You need more information to answer this question. d) White fur, long tail e) Brown fur, short tail   Part b Using the information given in Part a, if there were 400 mice in the F2 generation, how many do you expect would have white fur and long tails? a) 25 b) 186 c) 14 d) 372 e) 28 f) 75

When true-breeding mice with brown fur and short tails (BBtt)were crossed to true-breeding mice with white fur and long tails(bbTT), all of the F1 offspring had brown fur and long tails. TheF1 offspring were crossed to mice with white fur and short tails.What are the possible phenotypes of the F2 offspring? Which F2offspring are recombinant, and which are nonrecombinant? Whatare the ratios of phenotypes of the F2 offspring if independentassortment is taking place? How are the ratios affected by linkage?

F1 hybrid is obtained from the following cross: Parent 1: AB/AB; d/d; E/E Parent 2: ab/ab; D/D; e/e Assume that all genes are sorted independently except for genes A and B, which are tightly linked and show zero recombination. Following a testcross of F1, what proportion of the F2 progeny will be phenotypically like parent 1?     1/4   1/16   1/32   9/64   1/8