Chapter 11: DNA Analysis

Deoxyribonucleic acid

A complex molecule found in nearly all cells in all animals and plants.

Polymerase Chain Reaction

A technique that is used primarily to increase the amount of DNA by amplification.

Homozygous

It is if a person inherits the same form of a gene from the mother and the father.

Mitochondria

These are small structures located within practically all animal and plant cells.

Phenotype

Observed characteristic expressed by the gene.

Heterozygous

If the person receives different forms of the same gene (A and B)

Genotype

The alleles that make up that gene.

DNA

When _____ degrades, long strands may become fragmented.

Probe Hybridization

Used to visualize the VNTRs.

Restriction fragment length polymorphism

The first DNA typing method to be widely adopted by forensic biologists in the analysis of crime.

Polymer

A molecule made up of repeating simpler units, called monomers.

extraneous source

If care is not used in DNA extractions and typing, then biologic material from a(n) ______, such as the evidence technician, scientist, or laboratory technician, can be introduced accidentally.

Denaturation

The DNA is added to the PCR tube that contains the reaction mixture and is then heated to 94°C.

Genes

Sections of chromosomes that function in inheritance and the development of an embryo after conception.

Genetic Concordance

The relationship between two samples of DNA.

Allele

Each form of a particular gene at a particular locus in the genome.

Reverse dot blot

Process involves identifying the particular alleles present by reacting them with color- forming reagents on specially treated nylon strips.

RFLP

In ______, DNA is extracted from biologic material and then restriction enzymes are used to isolate small fragments of DNA called minisatellites or variable number tandem repeats (VNTRs) using restriction enzymes.

DQ alpha

______ and a number of other genes collectively called polymarker are typed using a method called reverse dot blot.

Cells

______ contain many mitochondria and each one has up to 10 copies of mtDNA.

forensic analysis

The goal of all ______ is to associate a piece of evidence with as few people or objects as possible, and ideally for there to be only one possible source.

STR markers

_____ exhibit high variability in a population, thus giving rise to high degrees of association of evidence with a suspect.

STRs

_____ have certain advantages over VNTRs that make them attractive for forensic comparison purposes.

Short Tandem Repeats

Combines some of the attributes of both PCR and RFLP.

Nuclear DNA

It has a geometric shape called a double helix.

MtDNA

It is circular in shape, containing 26, 569 base pairs and codes for 37 genes.

Helix

A spiral-shaped geometric figure.

CODIS system

The ________ consists of types of three databases categorized by the type of information they contain.

DNA

It is a remarkably stable substance, but it can degrade from a number of causes.

Polymerase chain reaction

Had been used since the 1970s for making copies (amplifying) of DNA using polymerase enzymes.

Short Tandem Repeats

These have the same basic arrangement as VNTRs in that they contain repeating units of base pair sequences in tandem.

DNA

It is located in two regions in a cell, the nucleus and mitochondria.

1100

MtDNA contains a noncoding region of _____ base pairs that, in turn, contains two hypervariable regions.

Adenine, Guanine, Cytosine, and Thymine

Four bases or nucleotides

Homozygous

If a person inherits the same form of a gene from the mother and the father

Heterozygous

If the person receives different forms of the same gene (A and B)

Allele

Each form of a particular gene at a particular locus in the genome

Phenotype

Observed characteristic expressed by the gene

Genotype

The alleles that make up that gene

Tandem Repeats

The repeats are right next to each other, without  any intervening base pairs

Restriction fragment length polymorphism (RFLP)

The first DNA typing method to be widely adopted by forensic biologists in the analysis of crime

Polymerase Chain Reaction (PCR)

A technique that is used primarily to increase the amount of DNA by amplification

Denaturation

The DNA is added to the PCR tube that contains the reaction mixture and is then heated to 94°C

Annealing

The next step in the PCR process is to attach a short strand of synthetic DNA to each of the separated strands

Human Leukocyte Antigen (HLA) DQ Alpha

First DNA region that was widely subjected to amplification and typing for forensic purposes by PCR

DQ Alpha

This gene exhibits sequence polymorphisms

Combined DNA Index System (CODIS)

The generic term used to describe the FBIs program of support for criminal justice DNA databases as well as the software used to run these databases