BIOL 202 Study Guide - Aa Battery

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carminecockroach406

22 Apr 2012

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Lecture 27 genetics of transposable elements. Barbara mcclintock & unstable alleles of maize: loss of a piece of a choromsome. Called ds locus for disocciator between centromere and ds: required presence of unlinked activator (ac) locus. Ds locus only broke when. Mobile elements, but only in the presence of ac (also a jumping gene) Unstable mutations of white eyes with red spots from dysgenic cross. Could find the same sequence in the large gal- allele at multiple times in the chromosome. In e. coli, there were several mobile elements making it unstable. Te insertions or movements that occur in germline cells will be passed on to (stable mutant) progeny. This most likely could be due to imprecise transposition of a transposable element. This is more likely to happen than one transposase! Transposon footprints that could knock out the function of something. Fate of progeny depends on whether somatic or germline event:

Related Questions

In the cells of all human females, one X chromosome is inactivated. The opsin1 gene is on the X chromosome and is expressed in the retinal cells of the eye. Mutations in this gene cause the recessive trait of colorblindness. Most women who have one mutant allele of the opsin1 gene and one normal allele of the opsin1 gene (they are heterozygous) can still see color. What is the most likely explanation for this finding? Question 20 options:

A) If the active X has the mutant allele of opsin1 gene, the inactive X with the normal allele will be reactivated.

B) Any mutations in the opsin1 gene on the active X can be corrected through genetic exchange (recombination) with the inactive X.

C) Some retinal cells will have an active X with the mutant allele of the opsin1 gene, and some will have an active X with the normal allele of the opsin1 gene.

D) The X with the mutant allele of the opsin1 gene is more likely to be inactivated because of the opsin1 mutation.

amberyellowjacket863

1. You want to determine the linear order and genetic distance between three genes on chromosome II in Drosophila. The recessive mutant alleles are g, m, and o. You cross heterozygous females to homozygous recessive males, score the phenotypes of progeny and obtain the following:

540 g m +

560 + + o

162 + m +

170 g + o

245 g + +

240 + m o

46 g m o

37 + + +

a) Determine the orientation of mutant vs. wild type alleles on the female parentâs chromosomes and then determine the gene order.

b) Calculate the distance between the three genes and draw the genetic map.

d) Calculate interference and provide a brief verbal interpretation of your result.

In a lab strain of Drosophila, cinnabar (cn) and brown (bw) are recessive eye color mutations known to be 41 map units apart on chromosome 2. When similar mutant alleles were induced in a strain from nature, the same linkage of cn and bw was observed. However, when a wildtype strain from nature was crossed with a cn bw/cn bw lab strain to create the genotype + +/cn bw, and females of this type were testcrossed to cn bw/cn bw males from the lab strain, the following phenotypic proportions were obtained in the progeny:

+ + 25,200

cn bw 21,009

cn + 11

+ bw 36

a) What is unexpected about these results?

b) What is the most likely explanation? (Summarize your model with a chromosome diagram with labeled genes.)

c) On your diagram show the precise origin of the cn + and the + bw classes.

BIOL 202 Study Guide - Aa Battery

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