Biology Homework Chapter 12: DNA Profiling and Genomics
Textbook assignment: Chapter 12: DNA Technology and Genomics, sections 11-21.
- 12.11 DNA sequencing and matching (sometimes called DNA fingerprinting) can identify individuals as the source of cells (like blood or hair) at a crime scene; they can also be used to identify inheritance through family trees.
- 12.12: The polymerase chain reaction (PCR) can be used to produce milliions of copies of a specific DNA fragment for study.
- 12.13: In gel electrophoresis, DNA segments cut using specific restriction enzymes can be "sorted" by passing electric current through a gel containing the segments. The lighter segments travel further than those of greater weight, effectively sorting the sequence by length.
- 12.14: Short tandem repeats (STRs) are nucleotide sequences that repeat over and over in the inron between actual genes. The number of repeats can vary in individual humans. Analyzing DNA for STRs at multiple sites allows forensic specialists to identify the individual who is the source of the DNA.
- 12.15: DNA profiling techniques can be used not only to place individuals at a crime scene, but also to identify victims of disasters where traditional methods are not possible, and to solve "cold" cases or compare DNA evidence from ancient sources with modern species.
- 12.16: Single nucleotide polymorphisms (SNPs) are differences in individual base pairs that occur in a given gene. When these occur at a restriction site, they can alter the ability of a restriction enzyme to cut the DNA, changing the length of DNA fragments produced by a given restriction enzyme. These differences or restriction fragment length polymorphisms (RLFPs) can also be used to rapidly determine whether DNA samples match or are different.
- 12.17: Genomics studies complete genomes — the complete DNA sequences for all chromosomes for a particular organism. Having complete sequences allows us to compare genes for specific protein production, and identify similarities in genetic makeup between different organisms.
- 12.18 The Human Genome project was designed to identify all the genes in human chromosomes.
- 12.19: The whole genome shotgun method allows researchers to chop an entire human DNA genome into restriction fragments and analyze them using computer techniques. While the method is relatively quick and cheap, there are some problems.
- 12.20: Proteomics looks at the range of proteins actually produced by a given genome. These proteins can reveal difference in the overall DNA structure (including histone interference) not present in the DNA helix alone.
- 12.21 Comparisons of genomes are used by biologists to determine how closely related organisms might be. We'll see how these comparisons feed into evolutionary theories.
Read the following weblecture before chat: Gene Sequencing and the Human Genome
Take notes on any questions you have, and be prepared to discuss the lecture in chat.
Perform the study activity below:
Work through the interactive exercise on Gel Electrophoresis to experience how biologists sort and measure DNA strands that have been cut with restriction enzymes.
Chat Preparation Activities
- Essay question: The Moodle forum for the session will assign a specific study question for you to prepare for chat. You need to read this question and post your answer before chat starts for this session.
- Mastery Exercise: The Moodle Mastery exercise for the chapter will contain sections related to our chat topic. Try to complete these before the chat starts, so that you can ask questions.
- Required: Complete the Mastery Exercise with a score of 85% or better.
- Optional: Test yourself with the textbook multiple choice questions and note any that you miss that still don't make sense. Bring questions to chat!
- Go to the Moodle and take the quiz for this chapter.
Read through the lab for this week; bring questions to chat on any aspect of the lab, whether you intend not perform it or not. If you decide to perform the lab, be sure to submit your report by the posted due date.
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