midterm2key

midterm2key - (20 points) 1. From the following linkage...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
(20 points) 1. From the following linkage data, construct a linkage map of genes a, b, c, and d. Show map distances between closest markers. Two-Factor Map Genes Distance (map units) d and c 10 mu c and a 13 mu a and d 3 mu b and c 18 mu b and d 8 mu From the testcross ( abc )/(+++) x ( abc )/( abc ), where the parentheses indicate that the order of genes a, b , and c is unknown, the following progeny were obtained. Phenotype Number a ++ 24 + b + 69 ++ c 2 ab + 4 a +c 75 + bc 20
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
abc 396 +++ 410 Total: 1,000 Construct a linkage map for genes a, b , and c . Indicate all map distances. Answer : (15 points) 2. You are given a strain of E. coli that contains one or more mutations. The rate of mutation, from + to - or - to +, is about 10 -7 per gene per experiment. You spread 10 8 cells of this strain without dilution onto eight different Petri dishes that contain the media indicated below. Expect mutation that occurs at low frequency will lead to exceptional colonies that grow under different selection conditions. Min = Minimal media +His = the amino acid histidine is added +Trp = the amino acid tryptophan is added +Tet = the antibiotic tetracycline is added. E. coli is normally sensitive to the killing effects of tetracycline (Tet s ), but resistant mutants (Tet R ) are known. The following patterns of growth occur on the eight plates: Note these are not replica plates.
Background image of page 2
(a) What is the genotype of this strain (describe any amino acid auxotrophy or drug resistance)? Answer : The strain is his - trp - tet s . (b) You isolate single colonies #1, #2, and #3 and retest their ability to grow on the following media. Indicate with a "+" or "-" whether cells from the isolated colony will grow. + = Cells will grow
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/30/2009 for the course LS 4 taught by Professor Ribaya during the Fall '08 term at UCLA.

Page1 / 9

midterm2key - (20 points) 1. From the following linkage...

This preview shows document pages 1 - 4. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online