2012 Quiz 1 Key - Biol241 2012 Quiz 1 (20 points) ...

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Unformatted text preview: Biol241 2012 Quiz 1 (20 points) Name:_____Key____________________ Purdue ID:__________________________ 1) A, B, C, D, E are 5 genes located on different autosomes. In all cases, the capital letter allele is dominant (i.e. A is dominant to a). In the following cross: AaBbCcDdEe (1st parent) x AabbCcddEE (2nd parent) What fraction of progeny will phenotypically resemble the 1st parent (2 points)? ¾ * ½* ¾* ½= 9/64 What fraction of progeny will genotypically resemble the 2nd parent (2 points)? ½ * ½ * ½ * ½* ½ = 1/32 2) Drosophila has 4 pairs of chromosomes (2n, n=4). Please complete the following table by indicating the number of chromosomes in these cells (6 points). Somatic cell at Spermatocyte at Spermatocyte at metaphase metaphase I metaphase II Number of 8 8 4 Chromosomes 3) You have obtained two mutant Drosophila strains without wings. To determine whether these two mutations are allelic, you should perform (2 points): A) Reciprocal crosses B) Testcrosses C) Complementation test D) Dihybrid crosses 4) In Drosophila, sex is determined by (2 points): A) The presence SRY gene on Y chromosome. B) The presence of X chromosomes. C) The environmental factor, such as temperature. D) The ratio of X chromosomes to autosomes. Biol241 2012 Quiz 1 (20 points) Name:_____Key____________________ Purdue ID:__________________________ 5) In Biol242, you isolated a mutant male fly that has short bristles (normal flies have long bristles). You crossed this mutant male with wild ­type virgin females and obtained the following F1 results: 15 males with short bristles 16 males with long bristles 15 females with short bristles 15 females with long bristles Based on these results, you conclude that the short bristle mutation is (2 points) A) Autosomal dominant B) Autosomal recessive C) X ­linked dominant D) X ­linked recessive 6) From the flies in question 5), you crossed some F1 males with short bristles with F1 females with short bristles, and obtained the following results: 30 males with short bristles 16 males with long bristles 31 females with short bristles 15 females with long bristles Please briefly explain the genetic basis for these results (2 points). The short bristle mutation is associated with recessive lethality. 7) In prophase I of meiosis, what are the structures that represent crossovers between non ­sister chromatids of homologous chromosomes (2 points)? Chiasmata (Chiasma will be fine). ...
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This note was uploaded on 03/12/2012 for the course BIO 241 taught by Professor Henrychang during the Spring '11 term at Purdue University-West Lafayette.

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