\u00cd hva\u00f0a landi e\u00f0a landsv\u00e6\u00f0i eru rau\u00f0h\u00e6r\u00f0ir algengastir? Hvar er \u00cdsland \u00ed r\u00f6\u00f0inni hva\u00f0 var\u00f0ar hlutfall rau\u00f0h\u00e6r\u00f0ra? Er h\u00e6gt a\u00f0 sj\u00e1 me\u00f0 DNA-ranns\u00f3kn hva\u00f0an rau\u00f0h\u00e6r\u00f0ir \u00cdslendingar koma? Rautt h\u00e1r er algengast me\u00f0al Vesturlandab\u00faa, en n\u00e6r \u00f3\u00feekkt hj\u00e1 upprunalegum \u00e6ttb\u00e1lkum Afr\u00edku, Amer\u00edku og \u00c1stral\u00edu. Rautt h\u00e1r finnst a\u00f0 auki \u00ed nokkrum as\u00edskum \u00e6ttb\u00e1lkum. \u00cd Vestur-Evr\u00f3pu er \u00fea\u00f0 algengast \u00e1 Bretlandseyjum.<\/p>\n
T\u00ed\u00f0nin er h\u00e6st \u00e1 \u00cdrlandi og \u00ed Skotlandi (fr\u00e1 10-30% eftir sv\u00e6\u00f0um), en s\u00fdnu l\u00e6gri \u00ed Wales og svo Englandi. Rautt h\u00e1r er ansi algengt \u00ed Su\u00f0vestur-Noregi (um 10%), en t\u00ed\u00f0ni \u00feess er l\u00e6gri annars sta\u00f0ar \u00ed Skandinav\u00edu og Danm\u00f6rku. Svipa\u00f0a s\u00f6gu er a\u00f0 segja af meginlandi Vestur-Evr\u00f3pu, t\u00ed\u00f0nin l\u00e6kkar me\u00f0 fjarl\u00e6g\u00f0 fr\u00e1 Bretlandseyjum. Um 8% \u00edslenskra kvenna og 6% \u00edslenskra karlmanna eru rau\u00f0h\u00e6r\u00f0. Rautt h\u00e1r er arfgengt. Ef einstaklingur er arfhreinn um st\u00f6kkbreytingu\/ar \u00e1 geninu MC1R (e. melanocortin-1 receptor) \u00fe\u00e1 ver\u00f0ur h\u00e1r hans rautt (sj\u00e1 n\u00e1nar \u00ed svari \u00deur\u00ed\u00f0ar \u00deorbjarnard\u00f3ttur vi\u00f0 spurningunni Eru litningar \u00ed rau\u00f0h\u00e6r\u00f0um eitthva\u00f0 galla\u00f0ir?) Gen eru strengur \u2013 oft \u00fe\u00fasund e\u00f0a fleiri \u00fe\u00fasund basa langur. Basarnir eru fj\u00f3rir, oftast t\u00e1kna\u00f0ir me\u00f0 b\u00f3kst\u00f6fum (A, C, G og T) og ver\u00f0a \u00feeir a\u00f0 vera \u00ed r\u00e9ttri r\u00f6\u00f0 til a\u00f0 afur\u00f0 gensins myndist og starfi e\u00f0lilega. St\u00f6kkbreytingar valda oft v\u00edxlum \u00e1 tilteknum b\u00f6sum, til d\u00e6mis ver\u00f0ur basi A \u00e1 sta\u00f0 241 \u00ed strengnum a\u00f0 basa G. \u00dea\u00f0 getur leitt til \u00feess a\u00f0 afur\u00f0 gensins skaddist e\u00f0a ey\u00f0ileggst alveg. R\u00e9tt eins og mataruppskriftir geta fari\u00f0 aflaga \u00e1 marga vegu, geta gen skemmst \u00e1 \u00f3l\u00edkan h\u00e1tt. \u00dev\u00ed eru margar \u00f3l\u00edkar st\u00f6kkbreytingar \u00ed MC1R geninu. Sumar eru alvarlegar en a\u00f0rar mildari. \u00dea\u00f0 fer eftir \u00fev\u00ed hva\u00f0a tv\u00e6r MC1R st\u00f6kkbreytingar einstaklingur er me\u00f0, hvers konar rau\u00f0an lit h\u00e1ri\u00f0 f\u00e6r. Rautt h\u00e1r er nefnilega ansi fj\u00f6lskr\u00fa\u00f0ugt, til d\u00e6mis br\u00fant me\u00f0 ro\u00f0aglans, rau\u00f0birki\u00f0 e\u00f0a lj\u00f3sgyllt. Einnig g\u00e6ti skipt m\u00e1li hva\u00f0a a\u00f0ra erf\u00f0a\u00fe\u00e6tti vi\u00f0komandi er me\u00f0, auk gallana \u00ed MC1R, en ekki ver\u00f0ur fari\u00f0 \u00fat \u00ed \u00fe\u00e1 s\u00e1lma h\u00e9r. Rautt h\u00e1r tengist st\u00f6kkbreytingu \u00e1 geninu MC1R. \u00deessi brosmildu tv\u00edburasystkini hafa fengi\u00f0 st\u00f6kkbreytt gen fr\u00e1 b\u00e1\u00f0um foreldrum \u00fear sem rautt h\u00e1r er v\u00edkjandi eiginleiki. Spurt var hvort a\u00f0 h\u00e6gt v\u00e6ri a\u00f0 sj\u00e1 me\u00f0 DNA-ranns\u00f3kn hva\u00f0an rau\u00f0h\u00e6r\u00f0ir \u00cdslendingar koma? Hugsum fyrst bara um MC1R-geni\u00f0. \u00dear sem rautt h\u00e1r getur orsakast af \u00f3l\u00edkum st\u00f6kkbreytingum og vegna \u00feess a\u00f0 t\u00ed\u00f0ni \u00feeirra er \u00f3l\u00edk milli landa og jafnvel landsv\u00e6\u00f0a, er m\u00f6guleiki a\u00f0 meta uppruna rau\u00f0h\u00e6r\u00f0ra \u00cdslendinga. Ef \u00e1kve\u00f0in st\u00f6kkbreyting \u00ed MC1R v\u00e6ri algengust \u00e1 Bretlandseyjum en \u00f6nnur st\u00f6kkbreyting v\u00e6ri algengust \u00ed Noregi, \u00fe\u00e1 v\u00e6ri h\u00e6gt a\u00f0 greina hva\u00f0an rautt h\u00e1r tiltekins \u00cdslendings s\u00e9 \u00e6tta\u00f0. Ef vi\u00f0 gefum okkur a\u00f0 \u00feetta s\u00e9u einu tv\u00e6r breytingarnar \u00ed MC1R h\u00e9rlendis og b\u00e1\u00f0ar jafn algengar er d\u00e6mi\u00f0 einfalt. \u00de\u00e1 v\u00e6ri l\u00edklega helmingur rau\u00f0h\u00e6r\u00f0ra me\u00f0 eitt eintak af hvorri st\u00f6kkbreytingu, og \u00fev\u00ed me\u00f0 norskt\/breskt rautt h\u00e1r. Hvor fj\u00f3r\u00f0ungur hinna rau\u00f0h\u00e6r\u00f0u v\u00e6ru me\u00f0 anna\u00f0 hvort me\u00f0 norskt e\u00f0a skoskt\/\u00edrsk rautt h\u00e1r. En MC1R er bara hluti svarsins. \u00cd erf\u00f0amengi mannsins eru um 25.000 gen og hefur hvert \u00feeirra s\u00edna s\u00f6gu. \u00dear a\u00f0 auki eru genin innan vi\u00f0 2% af erf\u00f0amengi mannsins. \u00deegar spurt er um uppruna \u00cdslendinga (rau\u00f0h\u00e6r\u00f0ra e\u00f0a annarra) \u00fearf a\u00f0 taka eins konar \u201eme\u00f0als\u00f6gu\u201c allra genanna og erf\u00f0amengisins. \u00dea\u00f0 m\u00e1 jafnvel \u00edmynda s\u00e9r \u00fdkt d\u00e6mi. \u00cdslensk kona kann a\u00f0 vera arfhrein um st\u00f6kkbreytingu \u00ed MC1R (og \u00fev\u00ed rautt h\u00e1r) sem er komin fr\u00e1 Noregi, en st\u00e6rsti hluti erf\u00f0amengis hennar er samt \u00e6tta\u00f0ur fr\u00e1 Bretlandseyjum. A\u00f0 s\u00ed\u00f0ustu m\u00e1 geta \u00feess a\u00f0 MC1R er ekki einhamt, frekar en \u00f6nnur gen. Gallar \u00ed MC1R auka einnig l\u00edkurnar \u00e1 freknum, og h\u00fa\u00f0 arfbera er yfirleit mj\u00f6g lj\u00f3s og vi\u00f0kv\u00e6mari fyrir s\u00f3lbruna. Samfara eru auknar l\u00edkur \u00e1 sortu\u00e6xlum og \u00f6\u00f0rum h\u00fa\u00f0krabbameinum. Reyndar eru l\u00edkurnar \u00e1 h\u00fa\u00f0krabbameinum tengdar \u00fev\u00ed hversu mikla s\u00f3l f\u00f3lk f\u00e6r. St\u00f6kkbreytingar \u00ed MC1R tengjast ekki h\u00fa\u00f0krabbameinum h\u00e9rlendis en \u00ed s\u00f3lr\u00edkari l\u00f6ndum eins og Hollandi og Sp\u00e1ni eru tengslin ansi sterk. \u00devert \u00e1 sta\u00f0al\u00edmyndir valda breytingar \u00ed MC1R ekki gr\u00e6num augnlit. Breytingar \u00e1 OCA2-, SLC24A4- og TYR-genunum eru taldar mikilv\u00e6gastar fyrir gr\u00e6n augu. \u00cd stuttu m\u00e1li eru rau\u00f0h\u00e6r\u00f0ir menn algengastir \u00e1 Bretlandseyjum og \u00e1 vissum sv\u00e6\u00f0um \u00e1 Nor\u00f0url\u00f6ndum. Rautt h\u00e1r pr\u00fd\u00f0ir 6-8% \u00cdslendinga. T\u00ed\u00f0ni st\u00f6kkbreytinga sem auka l\u00edkur \u00e1 rau\u00f0u h\u00e1ri er \u00f3l\u00edk milli landsv\u00e6\u00f0a. M\u00f6gulega er h\u00e6gt a\u00f0 meta uppruna erf\u00f0a\u00fe\u00e1tta sem tengist rau\u00f0u h\u00e1ri einstaklinga, en \u00fea\u00f0 v\u00e6ri bara l\u00edtill hluti af erf\u00f0amenginu og \u00f3n\u00e1kv\u00e6mt mat \u00e1 erf\u00f0afr\u00e6\u00f0ilegum uppruna vi\u00f0komandi. \u00cdtarefni: Sulem P, Gudbjartsson DF, Stacey SN, Helgason A, Rafnar T, Magnusson KP, Manolescu A, Karason A, Palsson A, Thorleifsson G, Jakobsdottir M, Steinberg S, P\u00e1lsson S, Jonasson F, Sigurgeirsson B, Thorisdottir K, Ragnarsson R, Benediktsdottir KR, Aben KK, Kiemeney LA, Olafsson JH, Gulcher J, Kong A, Thorsteinsdottir U, Stefansson K. 2007. Genetic determinants of hair, eye and skin pigmentation in Europeans. Nature Genetics, 39(12):1443-52. Jonathan Rees 2\/4\/03. The roots of red hair | The Human Genome. (Sko\u00f0a\u00f0 13. 1. 2015). Gerstenblith MR, Goldstein A, Fargnoli MC, Peris K, Landi MT. 2007. Comprehensive evaluation of allele frequency differences of MC1R variants across populations. Human Mutation 28: 495-505. Arnar P\u00e1lsson. \u201eHvar eru rau\u00f0h\u00e6r\u00f0ir algengastir?\u201c. V\u00edsindavefurinn 5.2.2015. http:\/\/visindavefur.is\/?id=68878<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" \u00cd hva\u00f0a landi e\u00f0a landsv\u00e6\u00f0i eru rau\u00f0h\u00e6r\u00f0ir algengastir? Hvar er \u00cdsland \u00ed r\u00f6\u00f0inni hva\u00f0 var\u00f0ar hlutfall rau\u00f0h\u00e6r\u00f0ra? Er h\u00e6gt a\u00f0 sj\u00e1 me\u00f0 DNA-ranns\u00f3kn hva\u00f0an rau\u00f0h\u00e6r\u00f0ir \u00cdslendingar koma? Rautt h\u00e1r er algengast me\u00f0al Vesturlandab\u00faa, en n\u00e6r \u00f3\u00feekkt hj\u00e1 upprunalegum \u00e6ttb\u00e1lkum Afr\u00edku, … Halda \u00e1fram a\u00f0 lesa