Ch.11 DNA. DNA Structure and Function The gene is the fundamental unit of heredity. Genes are aligned on chromosomes. Each gene is composed of DNA (deoxyribonucleic.

Slides:



Advertisements
Similar presentations
DNA. How Do Cells Know What To Do? Inside the nucleus of any cell is a set of chromosomes that contain all the genetic material needed to control cell.
Advertisements

DNA Typing bsapp.com. bsapp.com DNA strands come from the nucleus or the mitochondria bsapp.com.
DNA Analysis Chapter 12. General DNA Information Double helix—two coiled DNA strands Composed of nucleotides—units containing a sugar molecule (deoxyribose),
Explain how crime scene evidence is
Techniques used to analyze DNA. DNA Replication DNA replicates itself prior to cell division. DNA replication begins with the unwinding of the DNA strands.
DNA Analysis.
DNA basics DNA is a molecule located in the nucleus of a cell Every cell in an organism contains the same DNA Characteristics of DNA varies between individuals.
Forensic Science Presents DNA. B. History 1. James Watson and Francis Crick—in 1953 discovered the configuration of the DNA molecule.
9-1 PRENTICE HALL ©2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE An Introduction By Richard Saferstein DNA: THE INDISPENSIBLE.
DNA. A. Terminology A. Terminology Chromosomes- strands of genetic material Chromosomes- strands of genetic material Genes- Fundamental unit of heredity.
1 Chapter 7 Chapter 7 DNA Fingerprinting Learning Goals: o Explain how crime scene evidence is collected and processed to obtain DNA o Describe how radioactive.
Deoxyribonucleic Acid (DNA) Forensic Science. Copyright © Texas Education Agency All rights reserved. Images and other multimedia content used with.
Chapter 13 DNA: The Indispensable Forensic Science Tool
DNA Created from several PowerPoints on the state’s website.
DNA Analysis. What is DNA? Deoxyribonucleic Acid Genes found on a chromosome are composed of DNA DNA contains all of our body’s genetic material.
Forensics DNA Unit Test. DNA typing had its beginnings in 1985 with the work of: Sir Alec Jeffries.
Mitochondrial vs. Nuclear DNA
Notes 13.2 DNA typing.
Basic Review of DNA. Biomolecules These are the molecules that make up all living things Carbohydrates Lipids Proteins-chains of amino acids Nucleic acids-chains.
DNA Indispensable Forensic Science Tool. Understanding DNA-1 What is it? Deoxyribonucleic Acid-DNA Located in the nucleus of every cell in your body Contains.
13- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein.
9-1 PRENTICE HALL ©2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE An Introduction By Richard Saferstein DNA: THE INDISPENSIBLE.
9-1 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein DNA: THE INDISPENSIBLE.
Review Q’s What are three advantages gained from the decoding the human genome? diagnosing and treating genetic diseases understanding the causes of cancer.
DNA What is a DNA TEST.....Enjoy! ( Deoxyribonucleic Acid ) IF THAT DID NOT WORK ONE MORE TRY!
DNA Fingerprinting. Also known as DNA profiling Used in criminal and legal cases since the 1980’s to determine identity or parentage Also used to identify.
11- Criminalistics, 10e Richard Saferstein © 2011, 2007, 2004, 2001, 1998, 1995 Pearson Higher Education, Upper Saddle River, NJ All Rights Reserved.
9-1 PRENTICE HALL ©2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE An Introduction By Richard Saferstein Chapter 9.
 PCR Forensic Science 1/30/14. Drill  Q4-6 from the DNA Review Packet (pg. 3)  Q4. DNA is a large molecule created by linking a series of repeating.
DNA Evidence How is DNA used to solve crimes?
DNA The Indispensable Forensic Science Tool Tanya Ricketts.
13- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein.
 Finish Who Ate the Cheese? Begin PCR Info Forensic Science 12/5/14.
 DNA Analysis Forensic Science 12/1/14. Drill  Get new packet!  From which parent does mitochondrial DNA come?  Why did Tsar Nicholas give up his.
Forensic Science DNA Analysis 1. History of Biological Evidence in Forensics  DNA fingerprinting  Also known as DNA profiling  Used with a high degree.
All rights Reserved Cengage/NGL/South-Western © 2016.
History Evidence BIOLOGICAL EVIDENCE EXAMINED FOR INHERITED TRAITS TECHNIQUES EMERGED FROM HEALTHCARE DNA FINGERPRINTING DEVELOPED IN 1984.
Chapter 9 DNA: The Indispensable Forensic Science Tool.
Forensic Analysis of DNA. DNA Unlike hair and serology, DNA is one of the rare pieces of evidence that can be statistically linked to a single person.
DNA Deoxyribonucleic Acid. DNA Review Genetic material (DNA) is found in the nucleus of cells, and is contained on chromosomes. An organism inherits chromosomes.
9-1 ©2011, 2008 Pearson Education, Inc. Upper Saddle River, NJ FORENSIC SCIENCE: An Introduction, 2 nd ed. By Richard Saferstein DNA: THE INDISPENSIBLE.
DNA Fingerprinting.
DNA Forensics 352 – O’Dette. Why DNA? DNA is individual evidence DNA links or eliminates a suspect to a crime DNA identifies a victim even if no body.
DNA Fingerprinting Review. Why DNA? DNA is individual evidence DNA links or eliminates a suspect to a crime DNA identifies a victim even if no body is.
The Indispensable Forensic Science Tool Tanya Ricketts
All rights Reserved Cengage/NGL/South-Western © 2016.
5/14/2018 DNA Analysis.
Chapter 13 DNA: THE INDISPENSIBLE FORENSIC SCIENCE TOOL
DNA Review Packet.
All rights Reserved Cengage/NGL/South-Western © 2016.
Chapter 10: DNA.
DNA: THE INDISPENSIBLE FORENSIC SCIENCE TOOL
Try not to leave any behind – I dare you!
The Indispensible Forensic Science Tool
What do these items have to do with one another?
DNA Fingerprinting DNA Profiling.
DNA Analysis Forensics Chapter 11.
Unit 4: DNA Evidence Structure of DNA.
1 DNA.
Try not to leave any behind – I dare you!
Ch. 11: DNA Analysis.
DNA: THE INDISPENSIBLE FORENSIC SCIENCE TOOL
DNA.
DNA: THE INDISPENSIBLE FORENSIC SCIENCE TOOL
DNA Analysis “The capacity to blunder slightly is the
The Indispensable Forensic Tool
CHAPTER 13 DNA: The Indispensable Forensic Science Tool
Try not to leave any behind – I dare you!
9-4 Short Tandem Repeats.
Presentation transcript:

Ch.11 DNA

DNA Structure and Function The gene is the fundamental unit of heredity. Genes are aligned on chromosomes. Each gene is composed of DNA (deoxyribonucleic acid) specifically designed to control genetic traits of our cells. In the 1950s two researchers, James Watson and Francis Crick, deduced the structure of DNA.

DNA Structure and Function DNA is constructed as a very large molecule (polymer) made by linking a series of repeating units called nucleotides (monomers). A nucleotide is composed of a sugar molecule, a phosphorus atom surrounded by four oxygen atoms, and a nitrogen- containing molecule called a base.

DNA Structure and Function Four types of bases are associated with the DNA structure: adenine (A), thymine (T), guanine (G), and cytosine (C). The bases on each strand of DNA are aligned in a double-helix configuration so that adenine pairs with thymine and guanine pairs with cytosine (This concept is known as complimentary base pairing). The order in which the base pairs are arranged defines the role and function of a DNA molecule.

DNA Replication DNA replication begins with the unwinding of the DNA stands in the double helix. The double helix is re-created as the nucleotides are assembled in the proper order (A-T, C-G). Two identical copies of DNA emerge from the process. PCR (polymerase chain reaction) is a technique for replicating or copying a portion of a DNA strand outside a living cell. Recombinant DNA is a process by which the DNA of an organism is altered by inserting into it fragments of DNA from another organism.

DNA Typing Portions of the DNA molecule contain sequences of bases that are repeated numerous times. These tandem repeats offer a means of distinguishing one individual from another through DNA typing. Forensic scientists first began applying DNA technology to human identity in 1985.

DNA Typing Length differences associated with relatively long repeating DNA strands – called restriction fragment length polymorphisms (RFLPs) – formed the basis for one of the first DNA-typing procedures (until the mid-1990s) In the laboratory, DNA molecules are cut up by restriction enzymes and the resulting fragments are sorted out by electrophoresis.

DNA Typing Materials undergoing electrophoresis are forced to move across a gel-coated plate under the influence of an electrical potential. Substances such as DNA can be separated and characterized using electrophoresis. A typical DNA fragment pattern shows two bands (one RFLP from each chromosome)

Polymerase Chain Reaction Polymerase Chain Reaction (PCR) can amplify minute quantities of DNA. The technique evolved from an understanding of how DNA strands naturally replicate within a cell. PCR technology cannot be applied to RFLP DNA typing because RFLP strands are too long, often numbering in the thousands of bases.

Polymerase Chain Reaction PCR is best used with DNA strands that are no longer than a couple of hundred bases. Long RFLP strands tend to break apart under the adverse conditions at many crime scenes. The shorter DNA strands used in PCR are more stable and less subject to degradation caused by adverse environmental conditions.

Short Tandem Repeats (STRs) STRs are locations on the chromosome that contain short sequences that repeat themselves within the DNA molecule. They serve as useful markers for identification because they are found in great abundance throughout the human genome. The entire strand of an STR is very short, less than 450 bases long.

Short Tandem Repeats (STRs) This makes STRs much less sesceptible to degradation and they are often recovered from bodies or stains that have been subjected to extreme decomposition. The more STRs one can characterize, the smaller the percentage of the population from which a particular combination of STRs can emanate. This gives rise to the concept of multiplexing, in which the forensic scientist can simultaneously extract and amplify a combination of different STRs.

Short Tandem Repeats (STRs) With STR, as little as 125 picograms (picogram equals one-trillionth of a gram) of DNA (a human cell has an estimated 7 picograms of DNA so only 18 DNA- bearing cells are needed to obtain an STR profile) is required for analysis – 1/100 the amount normally required for RFLP analysis – can use only 9 cells with technology (low copy number).

Mitochondrial DNA Mitochondrial DNA (mtDNA) is located outside the cell’s nucleus and is inherited from the mother. Two regions of mitochondrial DNA, HV1 and HV2, are sequenced for forensic typing purposes. Forensic scientists rely on mtDNA to identify a subject when nuclear DNA is significantly degraded, such as in charred remains, or when nuclear DNA may be present in only very small quantities.

Mitochondrial DNA mtDNA analysis is significantly more sensitive than nuclear DNA profiling but does not approach STR analysis in its discrimination power. Forensic analysis of mtDNA is more rigorous, time consuming, and more costly than nuclear DNA profiling – for these reasons the FBI lab strictly limits the types of cases in which it will apply mtDNA technology.

Combined DNA Index System (CODIS) CODIS is a computer software program developed by the FBI that maintains local, state, and national databases of DNA profiles from convicted offenders, unsolved crime-scene evidence, and profiles of missing people.

Collection and Preservation of Biological Evidence for DNA Analysis All body fluids and biologically stained materials must be handled with a minimum of personal contact – use latex gloves to avoid infectious materials and to avoid contamination. Biological evidence should not be packaged in a plastic or airtight containers because the accumulation of residual moisture could contribute to the growth of blood-destroying bacteria and fungi.