Editing DNA profiling (section)

===DNA mixtures===
Mixtures are another common issue faced by forensic scientists when they are analyzing unknown or questionable DNA samples. A mixture is defined as a DNA sample that contains two or more individual contributors.<ref name="Forensic DNA Typing"/> That can often occur when a DNA sample is swabbed from an item that is handled by more than one person or when a sample contains both the victim's and the assailant's DNA. The presence of more than one individual in a DNA sample can make it challenging to detect individual profiles, and interpretation of mixtures should be performed only by highly trained individuals. Mixtures that contain two or three individuals can be interpreted with difficulty. Mixtures that contain four or more individuals are much too convoluted to get individual profiles. One common scenario in which a mixture is often obtained is in the case of sexual assault. A sample may be collected that contains material from the victim, the victim's consensual sexual partners, and the perpetrator(s).<ref>{{cite journal | vauthors = Weir BS, Triggs CM, Starling L, Stowell LI, Walsh KA, Buckleton J | title = Interpreting DNA mixtures | journal = Journal of Forensic Sciences | volume = 42 | issue = 2 | pages = 213–222 | date = March 1997 | pmid = 9068179 | doi = 10.1520/JFS14100J | url = https://projects.nfstc.org/workshops/resources/articles/Interpreting%20DNA%20Mixtures.pdf | access-date = 25 October 2018 | url-status = live | archive-url = https://web.archive.org/web/20200429055409/https://projects.nfstc.org/workshops/resources/articles/Interpreting%20DNA%20Mixtures.pdf | archive-date = 29 April 2020}}</ref>

Mixtures can generally be sorted into three categories: Type A, Type B, and Type C.<ref>{{cite book |last1=Butler |first1=John M. |title=Advanced topics in forensic DNA typing : interpretation |date=2015 |publisher=Academic Press |location=Oxford, England |isbn=978-0-12-405213-0 |page=140}}</ref> Type A mixtures have alleles with similar peak-heights all around, so the contributors cannot be distinguished from each other. Type B mixtures can be deconvoluted by comparing peak-height ratios to determine which alleles were donated together. Type C mixtures cannot be safely interpreted with current technology because the samples were affected by DNA degradation or having too small a quantity of DNA present.

When looking at an electropherogram, it is possible to determine the number of contributors in less complex mixtures based on the number of peaks located in each locus. In comparison to a single source profile, which will only have one or two peaks at each locus, a mixture is when there are three or more peaks at two or more loci.<ref>{{cite book |last1=Butler |first1=John M. |title=Advanced topics in forensic DNA typing : interpretation |date=2015 |publisher=Academic Press |location=Oxford, England |isbn=978-0-12-405213-0 |page=134}}</ref> If there are three peaks at only a single locus, then it is possible to have a single contributor who is tri-allelic at that locus.<ref>{{cite web |title=Tri-Allelic Patterns |url=https://strbase.nist.gov/tri_tab.htm |website=strbase.nist.gov |publisher=National Institute of Standards and Technology |access-date=6 December 2022}}</ref> Two person mixtures will have between two and four peaks at each locus, and three person mixtures will have between three and six peaks at each locus. Mixtures become increasingly difficult to deconvolute as the number of contributors increases.

As detection methods in DNA profiling advance, forensic scientists are seeing more DNA samples that contain mixtures, as even the smallest contributor can now be detected by modern tests. The ease in which forensic scientists have in interpenetrating DNA mixtures largely depends on the ratio of DNA present from each individual, the genotype combinations, and the total amount of DNA amplified.<ref>{{cite book | vauthors = Butler J |title=Forensic DNA Typing |date=2001 |publisher=Academic Press |chapter=Chapter 7 |pages=99–119}}</ref> The DNA ratio is often the most important aspect to look at in determining whether a mixture can be interpreted. For example, if a DNA sample had two contributors, it would be easy to interpret individual profiles if the ratio of DNA contributed by one person was much higher than the second person. When a sample has three or more contributors, it becomes extremely difficult to determine individual profiles. Fortunately, advancements in probabilistic genotyping may make that sort of determination possible in the future. [[Probabilistic genotyping]] uses complex computer software to run through thousands of mathematical computations to produce statistical likelihoods of individual genotypes found in a mixture.<ref>{{cite web |last1=Indiana State Police Laboratory |title=Introduction to STRmix and Likelifood Ratios |url=https://www.in.gov/isp/labs/files/STRmix_and_Likelihood_Ratios_IPAC%20and_Defense_Council_Training_2017.pdf |website=In.gov |access-date=25 October 2018 |archive-date=25 October 2018 |archive-url=https://web.archive.org/web/20181025190514/https://www.in.gov/isp/labs/files/STRmix_and_Likelihood_Ratios_IPAC%20and_Defense_Council_Training_2017.pdf |url-status=live }}</ref>

<big>'''DNA profiling in plant:'''</big>

Plant DNA profiling (fingerprinting) is a method for identifying cultivars that uses molecular marker techniques. This method is gaining attention due to Trade Related Intellectual property rights (TRIPs) and the Convention on Biological Diversity (CBD).<ref>{{Cite web |title=Plant DNA fingerprinting: an overview |url=https://www.researchgate.net/publication/228559903}}</ref>

'''<big>Advantages of Plant DNA profiling:</big>'''

Identification, authentication, specific distinction, detecting adulteration and identifying phytoconstituents are all possible with DNA fingerprinting in medical plants.<ref name="DNA Fingerprinting">{{Cite web |title=Application of DNA Fingerprinting for Plant Identification |url=http://www.jairjp.com/MARCH%202017/02%20SELVAKUMARI%20REVIEW.pdf}}</ref>

DNA based markers are critical for these applications, determining the future of scientific study in pharmacognosy.<ref name="DNA Fingerprinting" />

It also helps with determining the traits (such as seed size and leaf color) are likely to improve the offspring or not.<ref>{{Cite web |title=DNA fingerprinting in Agricultural Genetics Programs |url=https://www.biotech.iastate.edu/publications/biotech_info_series/bio7.html}}</ref>