WGSS 1105 Study Guide - Final Guide: Combined Dna Index System, Single-Nucleotide Polymorphism, Alec Jeffreys
23 Jan 2017
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Forensics
● Single nucleotide polymorphism (SNP) - microsatellite, when a single nucleotide in the
genome differs between members of a species
● Length polymorphism (STRs and VNTRs) - minisatellite, variation in the length of a DNA
fragment produced by a specific restriction enzyme acting on DNA from different
individuals that usually results from a genetic mutation and that may be used as a
genetic marker
● Restriction endonuclease - (aka restriction endonucleases) enzymes that cut a DNA
molecule at a particular place. They are essential tools for recombinant DNA technology.
● DNA probe - radioactively labeled fragment of DNA that can be used to detect the
presence of nucleotide sequences
● Probe hybridization - process of combining two complementary single-stranded DNA or
RNA molecules and allowing them to form a single double-stranded molecule through
base pairing.
● DNA fingerprint - banding pattern
● DNA profile - genotypes at many different loci, unique representation of a specific
individual
● Alec Jeffreys - researched gene evolution in sparrows and repetitive sequences in
human myoglobin gene; found: human genome contains many regions of hypervariable
gene (VNTR sequences), can serve as a unique identifier, genetic markers that differ
between humans are polymorphism
● PCR - currently use this method for DNA fingerprinting
● Allele - alternative sequence at a particular locus
● Locus - a particular position or location on a chromosome
● Capillary gel electrophoresis - A type of electrophoresis in which charged biomolecules
(e.g.,DNA) are separated by filling a capillary tube with a gel matrix, in which shorter
strands of DNA migrate more quickly than longer strands.
● CODIS loci - Combined DNA Index System and is the generic term used to describe the
FBI’s program of support for criminal justice DNA databases
● Mitochondrial DNA - DNA that is resistant to damage, continuous maternal line, non
recombining, small circular DNA genome
● Haplotype - a combination of alleles on the same chromosome that tend to be inherited
as a group, group of genes that are linked
M&M review
● Independent assortment - The process of random segregation and assortment of
chromosomes during anaphase I of meiosis resulting in the production of genetically
unique gametes.
● Segregation - during the production of gametes the two copies of each hereditary factor
segregate so that offspring acquire one factor from each parent.
● Recombination (crossing over) - the exchange of genes between homologous
chromosomes, resulting in a mixture of parental characteristics in offspring
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● Homologous chromosomes - chromosome pairs, one from each parent, that are similar
in length, gene position, and centromere location. The position of the genes on these are
the same, however the genes may contain different alleles
● Sister chromatids - refers to either of the two identical copies formed by the replication
of a single chromosome, with both copies joined together by a common centromere aka
one half of the duplicated chromosome
● Mitosis Stages - IPMAT
● Meiosis Stages - IPMATPMAT
● Tetrad - foursome during meiosis made by two homologous chromosomes that have
each already replicated into a pair of sister chromatids
● Pseudoautosomal regions (X and Y) - homologous sequences of nucleotides on the X
and Y chromosomes. Genetic recombination in the sex chromosomes occurs here,
inherited just like any autosomal genes
● SRY - a sex-determining gene/region on the Y chromosome in mammals that
determines maleness and is essential for development of the testes, testes determining
factor
Chromosomal Abnormalities 1 - Nondisjunction
● Haploid - having a single set of unpaired chromosomes
● Diploid - containing two complete sets of chromosomes, one from each parent
● Triploid - three copies of every chromosome instead of the normal two
● Polyploid - containing more than two homologous sets of chromosomes
● Monosomy - form of aneuploidy with the presence of only one chromosome from a pair
● Disomy - the condition of having a chromosome represented twice in a chromosomal
complement
● Trisomy - a condition in which an extra copy of a chromosome is present in the cell
nuclei, causing developmental abnormalities
● Aneuploidy - the state of having chromosomes in a number that is not an exact multiple
of the haploid number
● Nondisjunction - the failure of homologous chromosomes to properly segregate
● Trisomy 13 - Patau Syndrome
● Trisomy 18 - Edward Syndrome
● Trisomy 21 - Down’s syndrome
● Klinefelters syndrome - XXY (poor beard growth, breast development, under developed
testes
● Turners syndrome - XO, characteristic facial features, web of skin, constricted aorta,
poor breast development, under developed ovaries
● Homogametic - females, XX
● Heterogametic - males, XY
● Barr body - a small, densely staining structure in the cell nuclei of female mammals,
consisting of a condensed, inactive X chromosome. It is regarded as diagnostic of
genetic femaleness
Chromosomal Abnormalities 2
● Duplications - two gene loci have been duplicated independently of the chromosome
● Deletions - unequal crossover event during meiosis
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find more resources at oneclass.com
