Essay Example - Population Genetics and Genetic Advancements Use In Forensic Analysis

Published: 2023-08-29
Essay Example - Population Genetics and Genetic Advancements Use In Forensic Analysis
Type of paper:  Essay
Categories:  Forensic science Genetics Criminal justice Essays by wordcount
Pages: 7
Wordcount: 1736 words
15 min read

Genetic typing is a powerful tool for creating an identity in handling criminal cases especially when biological evidence is obtained at a crime scene which entails a missing person's character, victims in mass disaster identity, inheritance matters, and paternity testing. When there are biological materials, genetic evidence is gathered such as saliva, muscle tools, teeth, hair, bone, semen, and blood which can be used for microorganisms, plants, and animal characterization. Genetic markers repertoire applied for biological materials characterization has evolved continuously within the legal field with detection sensitivity, augmenting resolution, and simultaneous technology platform. Single nucleotide polymorphisms (SNP) provide forensic scientists with opportunities to distinguish an unknown person genetically.

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SNP is located within the human genome where nucleotide is present and differences among people. In the last two decades, polymorphic protein genetic markers were applied to identify people. Even though the use was creative, many factors altered in forensic applications based on protein-based genetic systems. The systems had a low discrimination power rendering individualization impossible. In most tissues, the presence of proteins is too small, which even makes the biological samples unstable, especially when placed to environmental insults.

SNPs are known to be genetic variation types found among human. About 1 percent of every population is reported to have the same nucleotide variation to be deemed as an SNP. In other words, SNPs are regarded to occur to about 300 nucleotides. Thus, it implies that when the human genome is about 3 billion nucleotides, the SNPs is likely to be 10 million. Approximately 99 percent of the genome is identical among people; thus, SNP enables people to learn more about differences in genetic roots appearing across races.

Random mating is choosing the mates independently of ancestry and genotypes at relative loci. Hardy-Weinberg proportion is the expected proportion that is relative to random mating. For instance, if the alleles A1, A2, and A3 have the percentage of P1, P2, and P3, respectively. The three allele's proportions are given at the top of the table, along the left margin. The genotypes, including its frequency, are provided at the interior of the table. The rate of homozygotes A1A1 is P12, and that of heterozygotes A2A3 is p2p3 +p3p2=2p2p3. The alleles proportion D2 and D4 are 0.109 and 0.271 in the white population (Bieber et al., 2019, p.125). When Hardy-Weinberg proportion is assumed, the sample allele proportion shall be treated like having true population frequencies where the genotype proportion of D2D2 shall be (0.109)2=0.012.

Genetic Variation

Genetic variation displays a natural occurrence of genetic differences among people of the same species. In essence, genetic variation allows survival and flexibility in changing environmental circumstances. In most instances, genetic variation is advantageous as it tends to be a preparation of unexpected results (Wienroth, 2018, p.18). For example, if the population interbreeds, it more likely for non-random mating to occur since a single organism opts to mate the other depending on specific traits. The choice is based on particular behaviors where the choices shape genetic combinations that are observed in a successive generation. If the situation is realized, the mating pattern of the population will not be random anymore.

In essence, non-random mating may be experienced in two aspects with completely different outcomes. Inbreeding is a form of non-random coupling where people are having similar genotypes have the greatest chance to mate with one another instead of people with different genotypes (Jeanguenat et al., 2017, p.419). Outbreeding is another non-mating process where people with specific genotype will more likely mate with people of a particular genotype. Outbreeding can result in increasing genetic variation as compared to inbreeding.

In some instances, there can be a random change in allele's numbers in a population. Thus, genetic drift occurs when the changes are relative to allele's frequency which can either decrease or increase with time. Small community do experience genetic drift in which infrequently-occurring alleles are more likely to be lost (Dror et al., 2017, p.833). When the process commences, genetic drift persists to the point alleles involved are suffered by the population. In essence, it causes the population genetic diversity to decrease.

If the population faces a population bottleneck, genetic drift is likely to occur. The condition occurs when significant numbers of individuals within the population die or restrained from breeding which in turns leads to a reduction in population size (Taylor et al., 2018, p. 43). Genetic drift can lead to rare allele's loss and can expand the gene pool size. In other words, genetic drift makes a new population to have distinctive genetic features from the original population rendering it to play a significant role in new species evolution.

Migration refers to organisms' movements from one place to another. In some instances, it may be in the form of cyclical patterns, when applied in population genetics, migration can be defined as the movement of people in and out of the defined population (Klein & Buoncristiani, 2017, p.110). For instance, when migrating individuals stay and mate with people within such a destination, they may offer sudden alleles' influx. When mating is created between destination and migration individuals, the people migrating may cause gametes that have alleles to alter the existing alleles' proportion.

Every genotype in a population has specific finesses in a particular environment. However, there is a chance for other genotypes to be favored which makes them reproduce. For those who are not favored, they are less likely to reproduce. Genotypes that are not favored may have different types like decreased access to resources, decreased access to inmates, and increased risk of predation (Campbell et al., 2017, p.454). The forces that contribute to relative allele frequencies are more likely to alter the population level, which in turns affects the selection forces that aligns them over successive generations.

Genetics Testing

Forensic scientists applied SNPs in analyzing situations such as missing persons and mass disaster cases where DNA, in most instances, are fragmented. In contexts where degraded fragments are smaller as compared to the expected STR typing length, then no outcomes will be obtained. Across the world assays every persons' markers profile, the short tandem repeats (STRs) is applied as a standard genetic forensic test (Slooten, 2017, p.11). STRs has genetic sequences just like minisatellites with the difference being a shorter repetition of DNA sequence. Among human, STRs seems to be equally variable with every new STR locus forensic scientists analyze where the odds become slightly smaller than two individuals who are likely to have same STRs at every locus.

Several human forensic casework is conducted through a standardized commercial called multiplexes that simultaneously assay STRs at different genetic loci. Currently, the application of STR profiles has resulted in large national databases development having million of people's profile convicted or suspected with crimes (Meakin etal., 2017, p.45). The DNA Identification Act of 1994, in the US, allowed the Federal Bureau of Investigation (FBI) to establish a national DNA database. The index systems had a convicted offender index which displayed DNA samples obtained from convicted victims and a forensic index that had DNA samples containing crime scene evidence. The Combined DNA Index System (CODIS) previously added indexes for missing persons and arrestees.

FBI's then queried CODIS based on STR profiles obtained from biological evidence obtained from a crime scene (Santos & Machado, 2017, p.311). When the crime scene evidence matches an offender' profile in the database, a correctional officer can use the information to exonerate or arrest the suspects. Police officers or investigators can search the forensic index can connect crimes when an individual DNA is obtained at both scenes.

HMS Ophthalmology Ocular Genomics Institute (OGI) and departmental investigators released a report on a comprehensive genetic test characterization and development for inherited eye disease that is reproducible and accurate. The research reveals that ear and eye and include every gene that causes mutations that cause early-onset glaucoma, optic atrophy, and inherited retinal degeneration (Teodorovic et al., 2017, p. 50). The above diseases lead to vision loss and other genetic treatments like gene therapy that is provided to people to preserve their vision. Research reveals that poor eyesight may occur along with families. Such when a person' parents are nearsighted, then a person is one to3 likely to be nearsighted.

SNPs within Population

SNPs are believed to have allele calling using chips and potentially automated typing which extend to commercials foods or products of Affymetrix and Illumina and some multiple-SNP guidelines such applied Biosystems products (Murphy, 2018, 399). The SNPs diallelic nature implies that allele calling is not a quantitative issue, but a qualitative problem which led to amenable to automation. In most instances, SNPs can be typed by applying short recognition sequences with a range of 45 to 55 bp. The short series is extremely valuable if DNA samples are degraded.

IrisPlex used for Forensic of Eye and Hair Color

In 2010, Susan Walsh and Manfred Kayser created the Irisplex systems that apply six DNA markers to assess whether others have brown or blue eyes (Vidaki & Kayser, M., 2017, p.238). Additional tags were included in 2012 to predict a person's hair colour. Later on, skin color was included, and the test was stored on a website where people can retrieve them at their point of convenience (Biedermann & Hicks, T., 2016, p.8). One of the common application was "Chedder Man" case which might have had a green or blue eye and dark to black skin. Over the last decades, HIrisPlex-S DNA system is used simultaneously to predict skin, hair, and eye color from trace DNA.

For instance, recent research on hair color genetic, assessed 300,000 individuals from European ancestry revealed that 110 new genetic markers associated with hair color (Szkuta et al., 2018, p.88). In this study, it was discovered that colors such as red or black are more reliable as compared to other colors such as brown and blonde. From this context, it can be argued that individual DNA codes on the physical feature are much better as compared to other groups based on different genetic databases that have European ancestry dominance.

Parabon's service develops a disclaimer that was orchestrated towards making reconstructions not to apply facial recognition. In future, the integration of the technology cannot be possible as it raises concerns about scope creep (Benschop et al., 2017, p.26). Such that, there is a need to develop innovative ways in masking genetic data which includes block-chain-based platforms, encryption, genome spiking, and genome cloaking.

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