Chapter 7: Problem 7
Explain the meaning of the term interference.
Chapter 7: Problem 7
Explain the meaning of the term interference.
All the tools & learning materials you need for study success - in one app.
Get started for freeIn the fruit fly, Drosophila melanogaster, a spineless (no wing bristles) female fly is mated to a male that is claret (dark eyes) and hairless (no thoracic bristles). Phenotypically wild-type \(\mathrm{F}_{1}\) female progeny were mated to fully homozygous (mutant) males, and the following progeny ( 1000 total) were observed: $$\begin{array}{lc} \text { Phenotypes } & \text { Number Observed } \\ \hline \text { spineless } & 321 \\ \text { wild } & 38 \\ \text { claret, spineless } & 130 \\ \text { claret } & 18 \\ \text { claret, hairless } & 309 \\ \text { hairless, claret, spineless } & 32 \\ \text { hairless } & 140 \\ \text { hairless, spineless } & 12 \end{array}$$ (a) Which gene is in the middle? (b) With respect to the three genes mentioned in the problem, what are the genotypes of the homozygous parents used in making the phenotypically wild \(F_{1}\) heterozygote? (c) What are the map distances between the three genes? A correct formula with the values "plugged in" for each distance will be sufficient. (d) What is the coefficient of coincidence? A correct formula with the values "plugged in" will be sufficient.
Three loci, mitochondrial malate dehydrogenase that forms \(a\) and \(b(M D H a, M D H b),\) glucouronidase that forms 1 and \(2(G U S 1\) \(G U S 2\) ), and a histone gene that forms \(+\) and \(-(H+, H-),\) are located on chromosome \(\\# 7\) in humans. Assume that the \(M D H\) locus is at position \(35, G U S\) at position \(45,\) and \(H\) at position 75 A female whose mother was homozygous for \(M D H a, G U S 2,\) and \(H+\) and whose father was homozygous for \(M D H b, G U S 1,\) and \(H-\) produces a sample of 1000 egg cells. Give the genotypes and expected numbers of the various types of cells she would produce. Assume no chromosomal interference.
In a series of two-point map crosses involving five genes located on chromosome II in Drosophila, the following recombinant \((\sin -\) gle- crossover) frequencies were observed:$$\begin{array}{lr} p r-a d p & 29 \\ p r-v g & 13 \\ p r-c & 21 \\ p r-b & 6 \\ a d p-b & 35 \\ a d p-c & 8 \\ a d p-v g & 16 \\ v g-b & 19 \\ v g-c & 8 \\ c-b & 27 \end{array}$$ (a) If the adp gene is present near the end of chromosome II (locus 83 ), construct a map of these genes. (b) In another set of experiments, a sixth gene ( \(d\) ) was tested against \(b\) and \(p r,\) and the results were \(d-b=17 \%\) and \(d-p r=23 \% .\) Predict the results of two-point maps between \(d\) and \(c, d\) and \(v g,\) and \(d\) and \(a d p\)
Review the Chapter Concepts list on page \(136 .\) Most of these center on the process of crossing over between linked genes. Write a short essay that discusses how crossing over can be detected and how the resultant data provide the basis of chromosome mapping.
Are sister chromatid exchanges effective in producing genetic variability in an individual? in the offspring of individuals?
What do you think about this solution?
We value your feedback to improve our textbook solutions.