Ch. 15 - Recombinant DNA Technology and Its Applications

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172당신이 사용하는 게 아니라요?교과서 변경

Sanders 3rd Edition

Ch. 15 - Recombinant DNA Technology and Its Applications

문제 E.6b

15장, 문제 E.6b

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.

검증된 단계별 안내

Step 1: Understand the concept of CODIS STR markers. CODIS (Combined DNA Index System) uses specific Short Tandem Repeat (STR) loci to compare DNA profiles. Each individual has two alleles per STR marker, one inherited from each parent, and these alleles are represented by the number of repeat units.

Step 2: Compare the STR alleles from the crime scene DNA (under the victim's fingernails) with the STR alleles of each suspect (A, B, and C) for all six markers. For each marker, check if the suspect's alleles match one or both alleles found in the crime scene sample.

Step 3: Determine if there is a failure to exclude a suspect by verifying if the suspect's alleles are consistent with the crime scene profile at every marker. A failure to exclude means the suspect's DNA profile could have contributed to the sample, i.e., no mismatches at any marker.

Step 4: If any suspect has one or more STR markers with alleles that do not match the crime scene DNA, that suspect is excluded as the source of the DNA under the victim's fingernails.

Step 5: Summarize your findings by stating which suspects, if any, cannot be excluded based on the STR marker comparison, and explain that a failure to exclude does not prove guilt but indicates that the suspect's DNA profile is consistent with the evidence.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

CODIS STR Markers

CODIS (Combined DNA Index System) uses Short Tandem Repeat (STR) markers, which are specific regions in DNA where short sequences repeat. These markers are highly variable among individuals, making them useful for identity matching in forensic analysis. Comparing STR profiles from crime scene samples and suspects helps determine if there is a genetic match.

Failure to Exclude in Forensic DNA Analysis

Failure to exclude means that a suspect's DNA profile cannot be ruled out as a source of the crime scene DNA. If the STR markers from a suspect match all the markers found in the evidence, the suspect is not excluded and remains a possible contributor. This does not confirm guilt but indicates the suspect’s DNA is consistent with the evidence.

Interpreting DNA Profiles for Identification

DNA profiles consist of alleles at multiple STR loci. To interpret, each locus from the crime scene is compared to suspects’ profiles. A complete match across all loci suggests the suspect’s DNA is present, while mismatches exclude suspects. Understanding how to read and compare these profiles is essential for forensic conclusions.

관련 실천

교과서 질문

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. Based on the exclusion principle, is either man excluded as the possible father? Explain.

645

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교과서 질문

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?

440

views

교과서 질문

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. In the 'C' column, label the DNA bands contributed by the mother with 'M' and the DNA bands contributed by the father with 'F.'

597

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교과서 질문

Using the genomic libraries, 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?

578

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교과서 질문

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.

430

views

교과서 질문

The human genome is 3×10⁹ bp. You wish to design a primer to amplify a specific gene in the genome. In general, what length of oligonucleotide would be sufficient to amplify a single unique sequence? To simplify your calculation, assume that all bases occur with an equal frequency.

628

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