Editing DNA paternity testing (section)

==DNA profiling==
[[File:DNA paternity testing en.svg|thumb|Example of DNA profiling in order to determine the father of a child (Ch). Child's DNA sample should contain a mixture of different size DNA bands of both parents. In this case, person #1 is likely the father.]]
{{Main|DNA profiling}}
The [[DNA]] of an individual is identical in all somatic (non reproductive) [[Cells (biology)|cells]]. During [[sexual reproduction]], the DNA from both parents combines to create a unique genetic makeup in a new cell. As a result, an individual's genetic material is derived equally from each parent. This genetic material is referred to as the nuclear [[genome]] because it is located in the [[Cell nucleus|nucleus]] of a cell.

Autosomal DNA testing allows for a comparison between the child's DNA, the mother's DNA, and the alleged father's DNA. By examining the genetic contribution from the mother, researchers can determine possible genotypes for the actual father. Specific sequences are examined to see if they were copied verbatim from one individual's genome; if so, then the genetic material of one individual could have been derived from that of the other (i.e. one is the parent of the other). If the alleged father cannot be excluded as the true father, then statistical analysis can be performed to assess how likely it is that the alleged father is the true father compared to a random man.<ref>{{cite book |last1=Butler |first1=John |title=Advanced Topics in Forensic DNA Typing: Interpretation |date=October 22, 2014 |publisher=Elsevier |isbn=9780124052130 |pages=349–400}}</ref>

In addition to nuclear DNA, [[Mitochondrion|mitochondria]] contain their own genetic material known as [[mitochondrial DNA]]. This mitochondrial DNA is inherited solely from the mother and is passed down without any mixing. As a result, establishing a relationship through the comparison of the mitochondrial genome is generally easier than doing so with the nuclear genome. However, testing the mitochondrial DNA can only confirm whether two individuals share a maternal ancestry; it cannot be used to determine paternity. Therefore, its application is somewhat limited.

In testing the paternity of a male child, the [[Y chromosome]] can be used for comparison, as it is inherited directly from father to son. Like mitochondrial DNA, the Y chromosome is passed down through the paternal line. This means that the two brothers share the same Y chromosome from their father. Therefore, if one brother is the alleged father, his biological brother could also be the father based solely on Y chromosomal data. This holds true for any male relative related to the suspected father along the paternal line. For this reason, autosomal DNA testing would provide a more accurate method for determining paternity. <ref>{{cite book |last1=Butler |first1=John |title=Forensic DNA Typing Biology, Technology, and Genetics of STR Markers |date=2005 |publisher=Elsevier |isbn=0-12-147952-8 |pages=201–240}}</ref>

In the US, the [[AABB]] has established regulations for DNA paternity and family relationship testing, although AABB accreditation is not mandatory. DNA test results can be considered legally admissible if the collection and  processing adhere to a proper chain of custody. Similarly, in Canada, the SCC has regulations on DNA paternity and relationship testing, while accreditation is recommended, it is not required.

The Paternity Testing Commission of the [[International Society for Forensic Genetics]] is responsible for creating biostatistical recommendations by the [[ISO/IEC 17025]] standards.<ref name="GjertsonBrenner2007">{{cite journal|last1=Gjertson|first1=David W.|last2=Brenner|first2=Charles H.|last3=Baur|first3=Max P.|last4=Carracedo|first4=Angel|last5=Guidet|first5=Francois|last6=Luque|first6=Juan A.|last7=Lessig|first7=Rüdiger|last8=Mayr|first8=Wolfgang R.|last9=Pascali|first9=Vince L.|last10=Prinz|first10=Mechthild|last11=Schneider|first11=Peter M.|last12=Morling|first12=Niels|title=ISFG: Recommendations on biostatistics in paternity testing|journal=Forensic Science International: Genetics|volume=1|issue=3–4|year=2007|pages=223–231|issn=1872-4973|doi=10.1016/j.fsigen.2007.06.006|pmid=19083766|s2cid=24450117 }}</ref> Biostatistical evaluations of paternity should be based on the likelihood ratio principle, resulting in the [[Paternity Index]] (PI). These recommendations offer guidance on the concepts of genetic hypotheses, calculation concerns necessary for producing valid PIs, as well as addressing specific issues related to [[population genetics]].