Editing Fingerprint (section)

== Genetics ==
Consensus within the scientific community suggests that the [[Dermatoglyphics#:~:text=Dermatoglyphics (from Ancient Greek derma,superficially similar pseudoscience of palmistry.|dermatoglyphic]] patterns on fingertips are hereditary.<ref name=":0">{{Cite journal |last=Hold |first=Sarah |date=1961 |title=Quantitative Genetics of Finger-Print Patterns |url=https://doi.org/10.1093/oxfordjournals.bmb.a069917 |journal=British Medical Bulletin |volume=17 |issue=3 |pages=247–250 |doi=10.1093/oxfordjournals.bmb.a069917 |pmid=13715551 |access-date=May 9, 2022 |archive-date=February 3, 2023 |archive-url=https://web.archive.org/web/20230203180409/https://academic.oup.com/bmb/article-abstract/17/3/247/288595?redirectedFrom=fulltext |url-status=live }}</ref> The fingerprint patterns between [[Twin#Monozygotic (identical) twins|monozygotic twins]] have been shown to be very similar (though not identical), whereas [[Twin#Dizygotic (fraternal) twins|dizygotic twins]] have considerably less similarity.<ref name=":0" /> Significant [[heritability]] has been identified for 12 dermatoglyphic characteristics.<ref>{{Cite journal |last1=Machado |first1=João Felipe |last2=Fernandes |first2=Paula Roquetti |last3=Roquetti |first3=Ricardo Wagner |last4=Filho |first4=José Fernandes |date=October 2010 |title=Digital Dermatoglyphic Heritability Differences as Evidenced by a Female Twin Study |journal=Twin Research and Human Genetics |language=en |volume=13 |issue=5 |pages=482–489 |doi=10.1375/twin.13.5.482 |pmid=20874471 |s2cid=31990988 |issn=1839-2628 |doi-access=free }}</ref> Current models of dermatoglyphic trait inheritance suggest [[Mendelian inheritance|Mendelian]] transmission with additional effects from either [[Additive genetic effects|additive]] or [[Dominance (genetics)|dominant]] major genes.<ref>{{Cite journal |last1=Sengupta |first1=M. |last2=Karmakar |first2=B. |date=2004-09-01 |title=Mode of inheritance of finger dermatoglyphic traits among Vaidyas of West Bengal, India |url=https://doi.org/10.1080/03014460412331287164 |journal=Annals of Human Biology |volume=31 |issue=5 |pages=526–540 |doi=10.1080/03014460412331287164 |pmid=15739382 |s2cid=11870062 |issn=0301-4460}}</ref>

Whereas genes determine the general characteristics of patterns and their type, the presence of environmental factors result in the slight differentiation of each fingerprint. However, the relative influences of genetic and environmental effects on fingerprint patterns are generally unclear. One study has suggested that roughly 5% of the total variability is due to small environmental effects, although this was only performed using total ridge count as a metric.<ref name=":0" /> Several models of finger ridge formation mechanisms that lead to the vast diversity of fingerprints have been proposed. One model suggests that a buckling instability in the [[Epithelium#Classification|basal cell layer]] of the fetal [[epidermis]] is responsible for developing epidermal ridges.<ref>{{Cite journal |last1=Kücken |first1=Michael |last2=Newell |first2=Alan C. |date=2005-07-07 |title=Fingerprint formation |url=https://www.sciencedirect.com/science/article/pii/S0022519304006198 |journal=Journal of Theoretical Biology |language=en |volume=235 |issue=1 |pages=71–83 |doi=10.1016/j.jtbi.2004.12.020 |pmid=15833314 |bibcode=2005JThBi.235...71K |issn=0022-5193 |access-date=May 9, 2022 |archive-date=August 25, 2018 |archive-url=https://web.archive.org/web/20180825142639/https://www.sciencedirect.com/science/article/pii/S0022519304006198 |url-status=live }}</ref> Additionally, blood vessels and nerves may also serve a role in the formation of ridge configurations.<ref>{{Cite journal |last=Kücken |first=Michael |date=2007-09-13 |title=Models for fingerprint pattern formation |url=https://www.sciencedirect.com/science/article/pii/S0379073807001284 |journal=Forensic Science International |language=en |volume=171 |issue=2 |pages=85–96 |doi=10.1016/j.forsciint.2007.02.025 |pmid=17459625 |issn=0379-0738 |access-date=May 9, 2022 |archive-date=December 28, 2011 |archive-url=https://web.archive.org/web/20111228072506/http://www.sciencedirect.com/science/article/pii/S0379073807001284 |url-status=live }}</ref> Another model indicates that changes in amniotic fluid surrounding each developing finger within the uterus cause corresponding cells on each fingerprint to grow in different microenvironments.<ref>{{Cite journal |last1=Jain |first1=Anil K. |last2=Prabhakar |first2=Salil |last3=Pankanti |first3=Sharath |date=2002-11-01 |title=On the similarity of identical twin fingerprints |url=https://www.sciencedirect.com/science/article/pii/S0031320301002187 |journal=Pattern Recognition |language=en |volume=35 |issue=11 |pages=2653–2663 |doi=10.1016/S0031-3203(01)00218-7 |bibcode=2002PatRe..35.2653J |issn=0031-3203}}</ref> For a given individual, these various factors affect each finger differently, preventing two fingerprints from being identical while still retaining similar patterns.

It is important to note that the determination of fingerprint inheritance is made difficult by the vast diversity of [[phenotype]]s. Classification of a specific pattern is often subjective (lack of consensus on the most appropriate characteristic to measure quantitatively) which complicates analysis of dermatoglyphic patterns. Several modes of inheritance have been suggested and observed for various fingerprint patterns. Total fingerprint ridge count, a commonly used metric of fingerprint pattern size, has been suggested to have a [[Polygene|polygenic]] mode of inheritance and is influenced by multiple additive genes.<ref name=":0" /> This hypothesis has been challenged by other research, however, which indicates that ridge counts on individual fingers are genetically independent and lack evidence to support the existence of additive genes influencing pattern formation.<ref>{{Cite journal |last1=Weninger |first1=M. |last2=Aue-Hauser |first2=G. |last3=Scheiber |first3=V. |date=December 1976 |title=Total finger ridge-count and the polygenic hypothesis: a critique |url=https://pubmed.ncbi.nlm.nih.gov/1017815 |journal=Human Biology |volume=48 |issue=4 |pages=713–725 |issn=0018-7143 |pmid=1017815 |access-date=May 9, 2022 |archive-date=February 3, 2023 |archive-url=https://web.archive.org/web/20230203180440/https://pubmed.ncbi.nlm.nih.gov/1017815/ |url-status=live }}</ref> Another mode of fingerprint pattern inheritance suggests that the arch pattern on the thumb and on other fingers are inherited as an autosomal dominant trait.<ref>{{Cite journal |last1=Slatis |first1=H. M. |last2=Katznelson |first2=M. B. |last3=Bonné-Tamir |first3=B. |date=May 1976 |title=The inheritance of fingerprint patterns |journal=American Journal of Human Genetics |volume=28 |issue=3 |pages=280–289 |issn=0002-9297 |pmc=1685016 |pmid=1266855}}</ref> Further research on the arch pattern has suggested that a major gene or [[Quantitative trait locus|multifactorial inheritance]] is responsible for arch pattern heritability.<ref>{{Cite journal |last1=Reed |first1=Terry |last2=Viken |first2=Richard J. |last3=Rinehart |first3=Shannon A. |date=2006-02-01 |title=High heritability of fingertip arch patterns in twin-pairs |url=https://onlinelibrary.wiley.com/doi/10.1002/ajmg.a.31086 |journal=American Journal of Medical Genetics Part A |language=en |volume=140A |issue=3 |pages=263–271 |doi=10.1002/ajmg.a.31086 |pmid=16411220 |s2cid=25789636 |issn=1552-4825}}</ref> A separate model for the development of the [[whorl]] pattern indicates that a single gene or group of linked genes contributes to its inheritance.<ref name=":1">{{Cite journal |last1=Yang |first1=Xiao |last2=Xiaojun |first2=Jin |last3=Yixuan |first3=Zhou |last4=Hui |first4=Liu |date=2016-08-22 |title=Genetic rules for the dermatoglyphics of human fingertips and their role in spouse selection: a preliminary study |journal=SpringerPlus |volume=5 |issue=1 |pages=1396 |doi=10.1186/s40064-016-3072-x |issn=2193-1801 |pmc=4993718 |pmid=27610315 |doi-access=free }}</ref> Furthermore, inheritance of the whorl pattern does not appear to be symmetric in that the pattern is seemingly randomly distributed among the ten fingers of a given individual.<ref name=":1" /> In general, comparison of fingerprint patterns between left and right hands suggests an asymmetry in the effects of genes on fingerprint patterns, although this observation requires further analysis.<ref>{{Cite journal |last1=Martin |first1=N.G. |last2=Eaves |first2=L.J. |last3=Loesch |first3=D.Z. |date=1982-01-01 |title=A genetical analysis of covariation between finger ridge counts |url=https://doi.org/10.1080/03014468200006061 |journal=Annals of Human Biology |volume=9 |issue=6 |pages=539–552 |doi=10.1080/03014468200006061 |pmid=7181445 |issn=0301-4460}}</ref>

In addition to proposed models of inheritance, specific genes have been implicated as factors in fingertip pattern formation (their exact mechanism of influencing patterns is still under research). Multivariate linkage analysis of finger ridge counts on individual fingers revealed linkage to [[Locus (genetics)|chromosome]] 5q14.1 specifically for the ring, index, and middle fingers.<ref>{{Cite journal |last1=Medland |first1=Sarah E. |last2=Loesch |first2=Danuta Z. |last3=Mdzewski |first3=Bogdan |last4=Zhu |first4=Gu |last5=Montgomery |first5=Grant W. |last6=Martin |first6=Nicholas G. |date=2007-09-28 |title=Linkage Analysis of a Model Quantitative Trait in Humans: Finger Ridge Count Shows Significant Multivariate Linkage to 5q14.1 |journal=PLOS Genetics |language=en |volume=3 |issue=9 |pages=1736–1744 |doi=10.1371/journal.pgen.0030165 |issn=1553-7404 |pmc=1994711 |pmid=17907812 |doi-access=free }}</ref> In mice, variants in the gene EVI1 were correlated with dermatoglyphic patterns.<ref name=":2">{{Cite journal |last1=Li |first1=Jinxi |last2=Glover |first2=James D. |last3=Zhang |first3=Haiguo |last4=Peng |first4=Meifang |last5=Tan |first5=Jingze |last6=Mallick |first6=Chandana Basu |last7=Hou |first7=Dan |last8=Yang |first8=Yajun |last9=Wu |first9=Sijie |last10=Liu |first10=Yu |last11=Peng |first11=Qianqian |date=2022-01-06 |title=Limb development genes underlie variation in human fingerprint patterns |journal=Cell |language=English |volume=185 |issue=1 |pages=95–112.e18 |doi=10.1016/j.cell.2021.12.008 |issn=0092-8674 |pmc=8740935 |pmid=34995520}}</ref> EVI1 expression in humans does not directly influence fingerprint patterns but does affect limb and digit formation which in turn may play a role in influencing fingerprint patterns.<ref name=":2" /> [[Genome-wide association study|Genome-wide association studies]] found [[Single-nucleotide polymorphism|single nucleotide polymorphisms]] within the gene ADAMTS9-AS2 on 3p14.1, which appeared to have an influence on the whorl pattern on all digits.<ref name=":3">{{Cite journal |last1=Ho |first1=Yvonne Y. W. |last2=Evans |first2=David M. |last3=Montgomery |first3=Grant W. |last4=Henders |first4=Anjali K. |last5=Kemp |first5=John P. |last6=Timpson |first6=Nicholas J. |last7=Pourcain |first7=Beate St |last8=Heath |first8=Andrew C. |last9=Madden |first9=Pamela A. F. |last10=Loesch |first10=Danuta Z. |last11=McNevin |first11=Dennis |date=2016-04-01 |title=Common Genetic Variants Influence Whorls in Fingerprint Patterns |url=https://www.jidonline.org/article/S0022-202X(15)00063-9/abstract |journal=Journal of Investigative Dermatology |language=English |volume=136 |issue=4 |pages=859–862 |doi=10.1016/j.jid.2015.10.062 |issn=0022-202X |pmc=4821365 |pmid=27045867 |access-date=May 9, 2022 |archive-date=February 3, 2023 |archive-url=https://web.archive.org/web/20230203180008/https://www.jidonline.org/article/S0022-202X%2815%2900063-9/fulltext |url-status=live }}</ref> This gene encodes [[antisense RNA]] which may inhibit ADAMTS9, which is expressed in the skin. A model of how genetic variants of ADAMTS9-AS2 directly influence whorl development has not yet been proposed.<ref name=":3" />

In February 2023, a study identified [[Wnt signaling pathway|WNT]], [[Bone morphogenetic protein|BMP]] and [[Ectodysplasin A receptor|EDAR]] as signaling pathways regulating the formation of primary ridges on fingerprints, with the first two having an opposite relationship established by a [[Turing reaction-diffusion system]].<ref>{{Cite journal |last1=Glover |first1=James D. |last2=Sudderick |first2=Zoe R. |last3=Shih |first3=Barbara Bo-Ju |last4=Batho-Samblas |first4=Cameron |last5=Charlton |first5=Laura |last6=Krause |first6=Andrew L. |last7=Anderson |first7=Calum |last8=Riddell |first8=Jon |last9=Balic |first9=Adam |last10=Li |first10=Jinxi |last11=Klika |first11=Václav |last12=Woolley |first12=Thomas E. |last13=Gaffney |first13=Eamonn A. |last14=Corsinotti |first14=Andrea |last15=Anderson |first15=Richard A. |date=2023-02-09 |title=The developmental basis of fingerprint pattern formation and variation |journal=Cell |volume=186 |issue=5 |pages=940–956.e20 |language=English |doi=10.1016/j.cell.2023.01.015 |issn=0092-8674 |pmid=36764291|s2cid=256701309 |doi-access=free |hdl=20.500.11820/3829bbbe-75f1-48fc-8f40-60fcd274c03f |hdl-access=free }}</ref><ref>{{Cite web |date=2023-02-09 |title=How fingerprints form was a mystery — until now |url=https://www.sciencenews.org/article/fingerprints-form-mystery |access-date=2023-02-15 |language=en-US}}</ref><ref>{{Cite journal |date=2023-02-09 |title=Why don't identical twins have the same fingerprints? New study provides clues |url=https://www.science.org/content/article/why-don-t-identical-twins-have-same-fingerprints-new-study-provides-clues |journal=[[Science (journal)|Science]] |language=en |doi=10.1126/science.adh0982}}</ref>