18. Molecular Genetic Tools

Methods for Analyzing DNA

Open Question
In this chapter, we focused on a number of interesting applications of genetic engineering, genomics, and biotechnology. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions?From GWAS how do we know which genes are associated with a particular genetic disorder?
Open Question
In this chapter, we focused on a number of interesting applications of genetic engineering, genomics, and biotechnology. At the same time, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions?

How does a positive ASO test for sickle-cell anemia determine that an individual is homozygous recessive for the mutation that causes sickle-cell anemia?
Open Question
Compare and contrast the terms Paternity Index (PI) and Combined Paternity Index (CPI). How does each contribute to paternity determination?
Open Question
What is the exclusion principle? How is it used in forensic genetic analysis and in paternity determination?
Open Question
What is the statistical principle underlying genetic health risk assessment? Why are these assessments not predictive of disease occurrence?
Open Question
You have constructed four different libraries: a genomic library made from DNA isolated from human brain tissue, a genomic library made from DNA isolated from human muscle tissue, a human brain cDNA library, and a human muscle cDNA library.Which of these would have the greatest diversity of sequences?
Open Question
You have constructed four different libraries: a genomic library made from DNA isolated from human brain tissue, a genomic library made from DNA isolated from human muscle tissue, a human brain cDNA library, and a human muscle cDNA library.Would the sequences contained in each library be expected to overlap completely, partially, or not at all with the sequences present in each of the other libraries?
Open Question
Using the genomic libraries in Problem 4, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.Assuming the human genome is 3x10⁹ and that the average insert size in the genomic libraries is 100 kb, how frequently will a clone representing myostatin be found in the genomic library made from muscle?
Open Question
Explain the meaning of 'identity by descent' in the context of identifying genealogical relationship between individuals. In these analyses, why are segments of chromosomes (haplotypes) rather than individual STRs used to identify genetic relationships?
Open Question
Using the genomic libraries in Problem 4, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.How frequently will a clone representing myostatin be found in the genomic library made from brain?
Open Question
Using the genomic libraries in Problem 4, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.How frequently will a clone representing myostatin be found in the cDNA library made from muscle?
Open Question
Using the genomic libraries in Problem 4, you wish to clone the human gene encoding myostatin, which is expressed only in muscle cells.How frequently will a clone representing myostatin be found in the cDNA library made from brain?
Open Question
A victim of murder is found to have scrapings containing skin cells under several of her fingernails. Genetic analysis confirms that the DNA isolated from these cells came from the same individual and does not match the DNA of the victim. The results shown below are for six CODIS STR markers from the crime scene DNA (from under the victim's fingernails and presumed to be the murderer's), and from three suspects (A, B, and C) who have been detained for questioning about the murder.Is there a failure to exclude any of the suspects? Explain.
Open Question
A victim of murder is found to have scrapings containing skin cells under several of her fingernails. Genetic analysis confirms that the DNA isolated from these cells came from the same individual and does not match the DNA of the victim. The results shown below are for six CODIS STR markers from the crime scene DNA (from under the victim's fingernails and presumed to be the murderer's), and from three suspects (A, B, and C) who have been detained for questioning about the murder.Do the STR results exclude any of the three suspects? Explain.
Open Question
The results shown are from a DNA test for four genes used in a paternity identification case. DNA for the mother (M) and her child (C) are shown along with DNA from two possible fathers, F1 and F2.What can you conclude based on the DNA results available?