Ro_Lecture4 - Lecture 4 1 Sex linked Described below is an...

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1 Lecture 4
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2 Sex linked Described below is an actual case history of the use of pedigree analysis: After the death of a wealthy individual (II:3), a man claiming to be his son (III:3) filed a paternity suit and claimed the inheritance. The deceased had only two living nephews (III:1 and III:2 who were sons of his brothers (II:1 and II:2). In determining whether the man was actually the son and had the rights to the inheritance which of the following markers would be most useful Autosomal X-linked Y-linked $$$
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3 Lethal alleles- Most of the mutations that we have discussed do not affect the viability of the individual. For example the mutations that produce white eyes in Drosophila or wrinkled yellow cotyledons in the plant do not disrupt viability. This means that the mutated gene is specifically involved in determining eye color and is not involved in processes central to viability of the fly. What would be the genetic consequences if we isolated a mutation that disrupted an enzyme that was critical for the viability of the fly? For example in Drosophila, Cy is a dominant mutation that produces Cy wings in the heterozygous condition but also behaves as a recessive lethal.
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4 Curly When a heterozygous Cy male is crossed to a heterozygous Cy female, Cy to non-Cy progeny are produced in a 2:1___ rather than the Mendelian 3:1___ ratio + = normal or wild type gene cy= dominant Cy mutation One explanation for the ___ rather than the expected ___ ratio is that Cy behaves as a recessive lethal mutation and cy/cy individuals die prior to reaching adulthood
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5 How would you test this hypothesis? Take the progeny and perform a test cross with the homozygous
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This note was uploaded on 04/15/2008 for the course BIO 105 taught by Professor Sullivan during the Fall '08 term at University of California, Santa Cruz.

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Ro_Lecture4 - Lecture 4 1 Sex linked Described below is an...

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