Dwarf parent: t Possible gametes: Tt 100% t Dwarf Tt 50% of F,'s are tall Test parent: Tt Possible gametes: tt 50% T 50% t Test parent: TT Possible gametes: 100% T t 100% of F,'s 50% of F,'s are tall are dwarf FIGURE 16-14 Test crosses to determine whether a plant with the dominant phenotype is heterozygous or homozygous. Of the data in this diagram, you would not know the genotypes of the test parents before the test cross; those data are what you are trying to discover. If you want to find only a single homozygote or heterozygote, you would need to do test crosses on only one or a few plants. Imagine, however, that you had done an experimental cross for a trait that you assumed would give you a 3:1 ratio; it would be necessary to do test crosses on a large number of progeny plants with the dominant phenotype just to confirm your experiment.

Dwarf parent: t Possible gametes: Tt 100% t Dwarf Tt 50% of F,'s are tall Test parent: Tt Possible gametes: tt 50% T 50% t Test parent: TT Possible gametes: 100% T t 100% of F,'s 50% of F,'s are tall are dwarf FIGURE 16-14 Test crosses to determine whether a plant with the dominant phenotype is heterozygous or homozygous. Of the data in this diagram, you would not know the genotypes of the test parents before the test cross; those data are what you are trying to discover. If you want to find only a single homozygote or heterozygote, you would need to do test crosses on only one or a few plants. Imagine, however, that you had done an experimental cross for a trait that you assumed would give you a 3:1 ratio; it would be necessary to do test crosses on a large number of progeny plants with the dominant phenotype just to confirm your experiment.

Name: When traits show complete dominance, the genotype can be revealed by a
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Description: When traits show complete dominance, the genotype can be revealed by a test cross. In the example of tall and dwarf plants (Figure) why is it necessary to use the dwarf parent? In general, why is it necessary to use a parent that is homozygous recess

Concepts of Biology

1st Edition

ISBN:9781938168116

Author:Samantha Fowler, Rebecca Roush, James Wise

Publisher:Samantha Fowler, Rebecca Roush, James Wise

Chapter8: Patterns Of Inheritance

Section: Chapter Questions

Problem 2ACQ: Figure 8.10 In pea plants, purple flowers (P) are dominant to white (p), and yellow peas (Y) are...

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In tomatoes, regular leaves (L) are multilobed and serrated and potato leaves (l) are broad, smooth, and single (Image 1). Red fruit (F) is dominant to yellow fruit (f). A cross is carried out between two pure lines of tomato plants, one having regular leaves and red fruit and the other having potato leaves and yellow fruit. The F1 generation all have regular leaves and red fruit. The F1 individuals are then crossed with one another. The information below represents two sets of data collected from the above cross. Phenotypes Data Set 1 Data Set 2 Regular Red 26 846 Regular Yellow 15 273 Potato Red 6 287 Potato Yellow 12 94 Total 59 1 500 Data set 1 is a from a small sample size and data set 2 is from a large sample size. Compare each data set to the expected probabilities. Explain any differences that you see in how different the observed results are from the expected results between the two data sets. Compare the expected probabilities of each phenotypic class to…
The genes for tall vine D and yellow seed G, are dominant over their respective alleles for dwarf d and green g. What phenotypes are expected from each of the following crosses? Include phenotypic and genotypic ratio. Use Punnet square to show the ff. Crosses. a. Heterozygous tall, homozygous yellow X Homozygous Tall, heterozygous yellow. b. Homozygous Dwarf, heterozygous yellow X Heterozygous tall, homozygous green
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yellow normal-54 yellow opaque-19 white normal- 15 white opaque-8 1. Diagram the hybrid cross showing the segregation of genes responsible for endosperm type andendosperm color in corn. Indicate all applicable gene relationships. Indicate the genotypes,phenotypes and gametes of individuals involved in all crosses. Derive the genotypic and phenotypicratios of the F2 generation using the branching method. 2. Interpret the result of your Chi-squared test.1. How many gene pairs wereresponsible for endosperm type andendosperm color in corn?2. What gene interaction was presentin the genes for the said traits?3. What are the dominant phenotypesfor each trait?4. What are the recessive phenotypesfor each trait?5. Are the genes independentlysegregating?6. What are the possible genotypes ofthe P1 and P2 that produced this F2population?7. Indicate your gene notation 3. Give the possible genotypes of each of the observed phenotypes in your sample. Determine thepossible genotypes of the parents of…
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When crossing 2 different parental strains of plants to establish the F1 generation, one of the assumptions that must be made in order to predict what the F1 phenotype will be is that.... both parsnts are heterozygous both parents are homozygous dominant both parents are homozygous recessive each patent is homozygous dominant for one trait and homozygous recessive for each other
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