ll Aha are under 3.5 feet tall. They produce a child of normal size. Describe th
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ll Aha are under 3.5 feet tall. They produce a child of normal size. Describe the alleles for the father, mother, and their child, respectively. Justify your answer. Essay #15: (OutlinedueJ an. 3; Essay due Jan. 8) The following data was collected using Drosophila melanogaster and two traits. In the parental cr that were homozygous dominant for both traits were crossed with flies that were homoz for both traits. The two traits that were analyzed were wild type wings (dominant) versus vestigial (recessive) and red eyes (dominant) versus cinnabar eyes (recessive). After the initial cross, Fi flies were crossed. e wings (dominant) yerous recessive Phenotypes Parent FliesFi Flies 2 Flies Wild type wings, red eyes Wild type wings, cinnabar eyes Vestigial wings, red eyes Vestigial wings, cinnabar eyes Totals 500 1200 985 45 35 310 1400 500 1000 1200 a. Describe the most probable explanation for how these two traits are inherited b. Explain how this data suggests that mode of inheritance. c. Explain the evidence that shows the recombination of these two traits. d. Explain how this mode of inheritance differs from the conclusions of Gregor MendelExplanation / Answer
a. The data states that each trait is controlled by a pair of hereditary genes. In F1 generation, one gene comes from each parent. The alleles (= forms) of the gene for wings and eyes are the same in true breeding flies ( WW, RR and ww, rr parents ). Cross breeding WW, RR with ww, rr flyes produces Ww,Rr progeny in the F1 generation. The F1 progeny receive a W and R allele from the dominent parent and w and r allele from the recessive parent. The F1 progenies have wild type wings and red eyes because the W and R allele is expressed and "cover up" the w and r allele. In F2 generation heterozygous individuals, only one allele, the dominant one, is able to express itself, while the other allele, the recessive, is hidden but still present, but In this generation we find sorting of alleles into new combinations other than parents, this new combinanation is apper due to linkage of genes. Linked genes, however, tend to stay together during the formation of gametes. Thus the result of test cross and self cross involving two genes genes yield different results, depending on whether the genes are linked or unlinked.
b. It is an X-linked, or sex-linked, mutation.Flies that carry two X chromosomes are female, and flies that carry one X and one Y are male. In flies, the Y chromosome is structurally different from the X chromosome, and it doesn’t carry genes that are complementary to those on the X, so any gene that is on the X in a male will be expressed, while the regular rules of dominant and recessive inheritance apply to female flies because they carry two X chromosomes. A cinnabar-eyed male must have the mutation on its single X chromosome. In a female fly, the mutation is inherited recessively, so two copies of the mutation are necessary to produce a cinnabar-eyed female
c. If a test cross between flies differing in two characters: eye color (Rr) and wing (Ww). The females are heterozygous at both genes and their phenotypes are wild type, so they display red eyes and wild type wings (RrWw). The males are homozygous recessive and express the mutant phenotypes for both characteristics, cinnabar eyes and vestigial wings (rrww). here we found that the parental phenotypes were disproportionately represented among offspring. If the two characters were on different chromosomes and assorted independently, we should have expected to see a ratio of recombinant phenotypes to parental phenotypes of 1:1:1:1. so the genes for eye color and wing in Drosophila are usually transmitted together from parents to offspring because they are located on the same chromosome. Therefore, cinnabar eye color gene and the vestigial wing gene are linked. This means these genes are located close to one another on the same chromosome.
d.Mendel concluded that a pair ofgene assort independently of one another but here we can see gene characterizing two different trait not always present on two different chromosome. When two are more genes resideon the same chromosome they are said to be linked and there transmission pattern is said to be linkage
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