SOLVED:”Prlco Final | Suppose ; you perfor RFLP family= gene mapping – locate Gcnc _ Xwhich causes Brncti = discas (affected individuals are indicated by shadowing – the pedigree givcn below) DNA samples Were taken from each family member; restriction cnzyme BamHI WES used cleate DNA; cicavage products were resolved by gel clectrophoresis; and Southemn analysis (hybridization) Wis performed using radioactive probe which specifically identifies DNA fragments at # variable BamHI cleavage site (RFLP site). Below the pedigree givcn an image of an uutoradiogram which shows polymomphic restriction fragments from cach individual. The linkage, ilany. between the gcne X an polymorphic BamHI sites unknown What is the best explanation of the obscrved results? gcnctic C distance from RFLP sile renc Xise Iap unils Benctic , distance from RFLP site gene X is S0 map units the RFLP site and gene X ure located diflerent nuclear chromosome the RFLP site is located on the = mitochondrial genome the RFLP site Autoradiogram: 3 kb 2kb Size BamHI fragnients decrecs ncruplvid coli cell? Which of the following best fli duplicaled region on the chronosomnc meroploid cells have coli cells do not exis prokaryoles alwuys ! haploid B) meroploid cells arc formed by fusion of two haploid cells meroploid complete and onc partial chromosome mncroploid coli cclls usually contain one coli cells are former F + cells which lost their Ftecior meroploid _ bctwecn them . Ioci _ and B are $0 closely linked that no recombinatiove iF Ppsojtcoy 32. Suppose thut two produce FI and the’ progeny crossed AAbb individual with an JaBB individual You cross What proportions. 40 You expect I0 sce in Fz? further t0 mrducc F2. What phenotypic ratios and in A) 3A-B- : aabb AAbk a8B B) !A-B- : 1A-bb : aaB- aabb Aa Bb Aa Bb C)I A-bb ; 2 A-B aAB- D) 9 A-B- : 3 A-bb : mB

A beautiful set of quantitative experiments on the lac operon were done by the Müller-Hill group in the 1990 s. where repression of expression of the lacZ gene was measured in a population of different mutant $E .$ coli cells. The mutant cells differed in the number, sequence, and position of the operator sites that bound the Lac repressor. In this problem, we explore how, using thermodynamic models of gene expression, these data can be used to obtain a number of quantities characterizing the Lac repressor-DNA interaction as well as DNA looping.
(a) Using the data from Oehler et al. (1994) shown in Figure 19.22 determine the in vivo binding energy of Lac repressor to each one of its operators and reproduce Figure 19.23
(b) Use your results from (a), and the repression measured by Oehler et al. (1994) in cells with two operators present, which leads to DNA looping, in order to determine the looping energy and to reproduce Figure 19.27
(c) As mentioned many times throughout the book, Müller et al. (1996) performed an experiment where the repression level was measured as a function of the distance between operators. The experiment and its results are shown in Figure 1.11 (p. 19 ). Based on their repression data and the thermodynamic models from the chapter, make a plot of the looping energy as a function of the interoperator distance. Show analytically that a maximum in repression corresponds to a minimum in looping energy. At what interoperator distance is the inferred looping free energy at a minimum? Is this consistent with the measured persistence length of DNA in vitro, which is $50 mathrm{nm} ?$
(d) Fit the looping energy obtained in (c) to the functional form $Delta F_{text {loop }}=a / N_{mathrm{bp}}+b ln N_{mathrm{bp}}+c N_{mathrm{bp}}+e .$ Use this looping
energy to make predictions about the outcome of a hypothetical experiment similar to the one performed by Müller et al. $(1996),$ but now using cells bearing $10,200,$ and 900 Lac repressor molecules per cell.
Relevant data for this problem are provided on the book’s website.


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