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1. Forensic Serology & DNA Typing…
M.PHOOL BADSHAH

2. Lecture-9
Population Variation in Forensic
Science

3. Introduction
• Population diversity is considered in forensic science, especially
when examining and interpreting DNA evidence.
• Understanding the genetic diversity of populations is essential for
accurately assessing the significance of DNA profiles and making
reliable inferences about the provenance of biological samples.
• In forensic science, population variety is significant in the following
ways:

4. 1- Diversity on Genetic Level:
 Due to past migrations, population isolations, and other demographic
events, distinct human communities have genetic diversity. The differences
in DNA markers utilized in forensic analysis reflect this variety.
2- Determination of Ancestor:
 Ancestry can be determined using genetic markers peculiar to a population.
The presence of markers in a person's DNA profile that are more prevalent
in particular populations can reveal details about their likely geographical
origins.
3- Allelic Frequencies:
 It tells us the relative prevalence of particular alleles in a population. To
estimate the rarity or commonality of a specific DNA profile in a given
population, one must be aware of allele frequencies.

5. 4- Databases in Forensics:
 Numerous populations' DNA profiles were kept in some population
databases, like the Combined DNA Index System (CODIS). Forensic
scientists can assess the evidential value of DNA evidence and ascertain the
likelihood of a match by comparing an individual's DNA profile to various
databases.
5- Considered Subpopulation :
 Finding subpopulation structures is important in larger populations.
Subpopulations may have different genetic compositions, and forensic
analyses may need to account for these variations to produce more accurate
interpretations.
6- Statistically Analyzed:
 The relevance of DNA evidence is evaluated and match probabilities are
computed using statistical techniques. Population genetics concepts like the
Hardy-Weinberg equilibrium and the product rule are frequently used in
these computations.

6. 7- Considered Ethically :
 It is imperative for forensic scientists to acknowledge the possibility of
imprecise or prejudiced analyses resulting from inadequate consideration of
demographic data. Errors in determining the strength of DNA evidence can
result from incorrect assumptions about population genetics.
8- Emerging Technologies:
 The development of high-throughput sequencing technology and genomics
has made it possible to analyze population variance in greater detail. This
may result in enhanced techniques for forensic ancestry determination and
an enhanced comprehension of the intricacies involved in population
genetics.