Lecture 15 Evaluation of the Strength of Forensic DNA Profiling

Mendelian Genetics

The study of inheritance patterns and gene variation as founded by Gregor Mendel.

Segregation of alleles

Mendel’s First Principle stating that each pair of alleles segregates from others during gamete formation.

Independent assortment

Mendel’s Second Principle indicating that each pair of alleles segregates independently of other pairs during gamete formation.

Diploid cells

Cells that have two complete sets of chromosomes, one from each parent.

Haploid cells

Cells that contain a single set of chromosomes, which is half the diploid number.

Linked genes

Genes that are located close together on the same chromosome and tend to be inherited together.

Genetic recombination

The exchange of genetic material between homologous chromosomes during meiosis.

Allele Frequency (p)

The measure of how common a particular allele is in a population.

Genotype Frequency (P)

The proportion of a specific genotype within a population.

Heterozygosity

A measure of genetic variation that represents the proportion of heterozygous individuals at a locus.

Hardy-Weinberg Principle

A principle that predicts genotype frequencies from allele frequencies under certain conditions.

Chi-square test

A statistical method to compare observed and expected frequencies to assess goodness of fit.

Population match probability (Pm)

Determines how likely it is to find a match between two random individuals in a population.

Profile Probability

A method to calculate the rarity of a DNA profile in a population.

Likelihood Ratio (LR)

A statistic that compares the probability of two hypotheses regarding the origin of DNA profiles.

Haplotypes

Combinations of alleles at different loci on a chromosome that are inherited together.

Linkage disequilibrium

The non-random association of alleles at different loci in a population.

θ factor

Correction factor used in DNA profiling calculations to account for subpopulation effects.