{"id":267,"date":"2014-08-19T12:47:05","date_gmt":"2014-08-19T12:47:05","guid":{"rendered":"http:\/\/uni.hi.is\/apalsson\/?p=267"},"modified":"2014-08-19T12:47:55","modified_gmt":"2014-08-19T12:47:55","slug":"science-web-human-genome","status":"publish","type":"post","link":"https:\/\/uni.hi.is\/apalsson\/IS\/2014\/08\/19\/science-web-human-genome\/","title":{"rendered":"Hva\u00f0 felst \u00ed \u00fev\u00ed a\u00f0 skr\u00e1 erf\u00f0amengi mannsins og hva\u00f0 hefur \u00fea\u00f0 \u00ed f\u00f6r me\u00f0 s\u00e9r?"},"content":{"rendered":"

Arnar P\u00e1lsson. \u201eHva\u00f0 felst \u00ed \u00fev\u00ed a\u00f0 skr\u00e1 erf\u00f0amengi mannsins og hva\u00f0 hefur \u00fea\u00f0 \u00ed f\u00f6r me\u00f0 s\u00e9r?<\/a>\u201c. V\u00edsindavefurinn<\/i> 18.8.2014. http:\/\/visindavefur.is\/?id=67876. (Sko\u00f0a\u00f0 19.8.2014).<\/p>\n

Hva\u00f0 felst \u00ed \u00fev\u00ed a\u00f0 skr\u00e1 erf\u00f0amengi mannsins og hva\u00f0 hefur \u00fea\u00f0 \u00ed f\u00f6r me\u00f0 s\u00e9r?<\/strong><\/div>\n

\u00deessari spurningu um skr\u00e1ningu erf\u00f0amengis mannsins var svara\u00f0 af Gu\u00f0mundi Eggertssyni \u00e1 fyrsta starfs\u00e1ri V\u00edsindavefsins, \u00e1ri\u00f0 2000. S\u00ed\u00f0an \u00fe\u00e1 hefur \u00fdmislegt gerst \u00e1 svi\u00f0i erf\u00f0av\u00edsindanna og \u00fev\u00ed full \u00e1st\u00e6\u00f0a til a\u00f0 svara spurningunni \u00e1 n\u00fdjan leik. Eldra svari\u00f0 stendur \u00fe\u00f3 enn fyrir s\u00ednu, sj\u00e1: Hva\u00f0 felst \u00ed \u00fev\u00ed a\u00f0 skr\u00e1 erf\u00f0amengi mannsins og hva\u00f0 hefur \u00fea\u00f0 \u00ed f\u00f6r me\u00f0 s\u00e9r?<\/a><\/p>\n

Erf\u00f0aefni\u00f0 \u00ed \u00f6llum l\u00edfverum \u00e1 j\u00f6r\u00f0inni er DNA-kjarns\u00fdra<\/a>. DNA er gormlaga<\/a> og ber \u00ed s\u00e9r uppl\u00fdsingar um byggingu og starfsemi l\u00edfvera, hin svok\u00f6llu\u00f0u gen<\/a>. Kjarns\u00fdran er tveir \u00fer\u00e6\u00f0ir sem tvinnast saman og parast me\u00f0 \u00e1kve\u00f0num einingum sem kallast kirni e\u00f0a basar. Kirnin parast samkv\u00e6mt efnafr\u00e6\u00f0ilegum eiginleikum \u00feannig a\u00f0 A parast vi\u00f0 T, og C parast vi\u00f0 G. \u00c1ri\u00f0 1970 var kunngj\u00f6r\u00f0 a\u00f0fer\u00f0 sem ger\u00f0i kleift a\u00f0 greina r\u00f6\u00f0 basa \u00ed b\u00fatum erf\u00f0aefnis. Margar l\u00edfefnafr\u00e6\u00f0ilegar a\u00f0fer\u00f0ir voru pr\u00f3fa\u00f0ar \u00ed upphafi og enn eru n\u00fdjar a\u00f0fer\u00f0ir \u00ed \u00fer\u00f3un. Saman eru \u00feessar a\u00f0fer\u00f0ir kalla\u00f0ar DNA-ra\u00f0greiningar, og \u00fe\u00e6r n\u00fdtast til a\u00f0 lesa r\u00f6\u00f0 basanna sem mynda genin og a\u00f0ra hluti erf\u00f0amengisins. Fyrsta ra\u00f0greiningin \u00e1 heilu erf\u00f0amengi var \u00e1 veirunni MS2 \u00e1ri\u00f0 1976 og fyrsta bakter\u00edan, Haemophilus influenzae<\/em>, var ra\u00f0greind 1995.<\/p>\n

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R\u00f6\u00f0 basa \u00ed DNA m\u00e1 greina me\u00f0 efnahvarfi \u00fear sem hver basi er lita\u00f0ur me\u00f0 s\u00e9rst\u00f6kum fl\u00faorlj\u00f3mandi h\u00f3pi. Mismunur \u00e1 sta\u00f0setningu og styrk lj\u00f3ss \u00e1 fj\u00f3rum bylgjulengdum segir til um r\u00f6\u00f0 basa \u00ed \u00e1kve\u00f0num DNA-b\u00fat e\u00f0a geni.<\/p>\n<\/div>\n<\/div>\n

Samfara t\u00e6kniframf\u00f6rum kom upp s\u00fa hugmynd a\u00f0 skr\u00e1 e\u00f0a ra\u00f0greina erf\u00f0amengi mannsins. \u00dea\u00f0 var mikil \u00e1skorun \u00fev\u00ed erf\u00f0amengi Homo sapiens<\/em> er m\u00f6rgum sinnum st\u00e6rra en erf\u00f0amengi veira og baker\u00eda<\/a>. MS2-veiran hefur um 3.000 kirnap\u00f6r en eitt sett af litningum okkar (23 alls) samanstendur af um \u00fea\u00f0 bil 3.200.000.000 kirnap\u00f6rum. Ef litningar mannsins v\u00e6ru skrifa\u00f0ir \u00fat \u00ed s\u00f6mu leturst\u00e6r\u00f0 og n\u00f6fn \u00ed s\u00edmaskr\u00e1, \u00feyrfti um 200 s\u00edmaskr\u00e1r til a\u00f0 rita \u00fat eitt erf\u00f0amengi (mi\u00f0a\u00f0 vi\u00f0 1000 bls. skr\u00e1r). Ra\u00f0greining erf\u00f0amengis mannsins var risavaxi\u00f0 verkefni, sem \u00fearfna\u00f0ist mikils skipulags og fj\u00e1rmagns. Bandar\u00edsk yfirv\u00f6ld, me\u00f0 li\u00f0sinni Kanadamanna og Breta h\u00f6nnu\u00f0u \u00ferepaskipt verkefni sem \u00e1tti a\u00f0 taka r\u00fam 10 \u00e1r. Einkaa\u00f0ilar, undir forystu Craig Venter, v\u00f6ldu a\u00f0ra n\u00e1lgun og f\u00f3ru \u00ed kapp vi\u00f0 hi\u00f0 opinbera. Markmi\u00f0 Venter var a\u00f0 s\u00e6kja um einkaleyfi \u00e1 genum. S\u00fa hugmynd var felld \u00fev\u00ed n\u00e1tt\u00farulegar erf\u00f0auppl\u00fdsingar l\u00edfvera eru ekki uppfinning. Engu a\u00f0 s\u00ed\u00f0ur var\u00f0 miki\u00f0 kapphlaup um a\u00f0 lj\u00faka ra\u00f0greiningu erf\u00f0amengisins. Kapphlaupinu lauk me\u00f0 jafntefli og sumari\u00f0 2000 var fyrsta \u00fatg\u00e1fa af erf\u00f0amengi mannsins kynnt \u00e1 bla\u00f0amannafundi \u00e1 t\u00fani \u00fe\u00e1verandi Bandar\u00edkjaforseta, Bills Clintons. V\u00edsindagreinar um erf\u00f0amengi\u00f0 birtust s\u00ed\u00f0an \u00ed febr\u00faar 2001. Me\u00f0 \u00fev\u00ed a\u00f0 skr\u00e1 erf\u00f0amengi mannsins var r\u00f6\u00f0 basanna \u00ed genum og \u00e1 litningum \u00e1kv\u00f6r\u00f0u\u00f0. Einnig var h\u00e6gt a\u00f0 skilja r\u00f6\u00f0 gena, byggingu og sta\u00f0setningu \u00feeirra \u00e1 litningum. Til d\u00e6mis byrjar geni\u00f0 Evx \u00e1 atggagagccgaaaggacatggttatgtttctgga, og \u00fea\u00f0 liggur vi\u00f0 hli\u00f0ina \u00e1 RNA-geninu HOTTIP. Ra\u00f0greiningin afhj\u00fapa\u00f0i l\u00edka a\u00f0ra hluti erf\u00f0amengja og litninga, eins og \u00fer\u00e1\u00f0h\u00f6ft, st\u00f6kkla, stj\u00f3rnsv\u00e6\u00f0i og endurtekningar. En t\u00e6knin og ra\u00f0greiningar eru \u00f3fullkomnar. Sum sv\u00e6\u00f0i \u00ed erf\u00f0amengi d\u00fdra og plantna hafa \u00fea\u00f0 margar endurtekningar og st\u00f6kkla a\u00f0 ekki hefur tekist a\u00f0 ra\u00f0greina \u00feau. Erf\u00f0amengi okkar er \u00feekkt a\u00f0 st\u00e6rstu leyti en nokkur hundru\u00f0 sl\u00edk g\u00f6t eru enn \u00f3fyllt. En ma\u00f0urinn \u00e1 ekki bara eitt erf\u00f0amengi. Vi\u00f0 eigum hvert tv\u00f6 eint\u00f6k af okkar eigin erf\u00f0amengi (eitt fr\u00e1 pabba og eitt fr\u00e1 m\u00f6mmu) og \u00feau eru ekki eins. \u00dev\u00ed \u00e1 mannkyni\u00f0 r\u00famlega 14 milljar\u00f0a erf\u00f0amengja (tv\u00f6 \u00ed hverjum einstaklingi). \u00c1st\u00e6\u00f0an er s\u00fa a\u00f0 \u00ed erf\u00f0aefninu eru fr\u00e1vik, breytingar \u00e1 st\u00f6kum kirnum e\u00f0a jafnvel heilum genum e\u00f0a litningahlutum. \u00deessi fr\u00e1vik kallast st\u00f6kkbreytingar<\/a> og \u00feau m\u00e1 til d\u00e6mis finna me\u00f0 \u00fev\u00ed a\u00f0 bera saman erf\u00f0amengi. \u00cd lj\u00f3s kemur a\u00f0 a\u00f0 minnsta kosti 15.000.000 sta\u00f0ir \u00ed erf\u00f0amengi mannsins eru breytilegir. \u00dear af lei\u00f0ir a\u00f0 allir eru erf\u00f0afr\u00e6\u00f0ilega einstakir. Breytileiki \u00e1 milli einstaklinga var ein af kveikjunum a\u00f0 ra\u00f0greiningu erf\u00f0amengis mannsins. Hugmyndin var a\u00f0 au\u00f0veldara v\u00e6ri a\u00f0 kortleggja gen sem tengjast sj\u00fakd\u00f3mum, ef vi\u00f0 vissum byggingu erf\u00f0amengisins. Kortlagning gena byggist \u00e1 a\u00f0 kanna hva\u00f0a st\u00f6kkbreytingar s\u00fdna fylgni vi\u00f0 sj\u00fakd\u00f3m e\u00f0a einkenni, til d\u00e6mis \u00feegar bornir eru saman 1000 astmasj\u00faklingar og 1000 heilbrig\u00f0ir (sj\u00e1 mynd).<\/p>\n

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Til a\u00f0 greina \u00e1hrif st\u00f6kkbreytinga er t\u00ed\u00f0ni \u00feeirra borin saman hj\u00e1 h\u00f3pi sj\u00faklinga me\u00f0 \u00e1kve\u00f0inn sj\u00fakd\u00f3m og samb\u00e6rilegum vi\u00f0mi\u00f0unarh\u00f3p. \u00cd \u00feessu tilb\u00fana d\u00e6mi eru \u00e1hrif tveggja st\u00f6kkbreytinga athugu\u00f0. Engin munur er \u00e1 t\u00ed\u00f0ni st\u00f6kkbreytingar \u00e1 basa 1 \u00ed l\u00f6snum og hraustum einstaklingum, en breyting \u00e1 basa 2 er greinilega algengari l\u00f6snum en heilbrig\u00f0um.<\/p>\n<\/div>\n<\/div>\n

\u00deegar b\u00fai\u00f0 er a\u00f0 sta\u00f0festa a\u00f0 st\u00f6kkbreyting tengist sj\u00fakd\u00f3mi \u00fe\u00e1 opnast m\u00f6guleiki \u00e1 d\u00fdpri skilningi \u00e1 sj\u00fakd\u00f3mnum og um lei\u00f0 me\u00f0fer\u00f0 e\u00f0a l\u00e6kningu. En \u00ed m\u00f6rgum tilfellum er bj\u00f6rninn ekki unninn \u00feegar st\u00f6kkbreyting finnst. Gu\u00f0mundur Eggertsson sag\u00f0i \u00e1ri\u00f0 2000:<\/p>\n

\u00deess er ekki a\u00f0 v\u00e6nta a\u00f0 ra\u00f0greining genamengisins valdi byltingu \u00ed mannerf\u00f0afr\u00e6\u00f0iranns\u00f3knum. Frekar m\u00e1 l\u00edta \u00e1 hana sem fyrsta \u00e1fangann til fulls skilnings \u00e1 erf\u00f0aefni mannsins og starfsemi \u00feess. N\u00e6sti \u00e1fangi ver\u00f0ur skilgreining \u00e1 ger\u00f0 og hlutverki allra \u00feeirra pr\u00f3t\u00edna sem \u00e1kv\u00f6r\u00f0u\u00f0 eru af erf\u00f0aefninu.<\/p><\/blockquote>\n

Or\u00f0 Gu\u00f0mundar eiga enn vi\u00f0. Jafnvel \u00fe\u00f3tt a\u00f0 vi\u00f0 finnum erf\u00f0a\u00fe\u00e1tt sem tengist sj\u00fakd\u00f3mi, \u00fe\u00e1 er mikil vinna fyrir h\u00f6ndum a\u00f0 skilja hvernig hann hefur \u00e1hrif \u00e1 sj\u00fakd\u00f3minn. \u00deetta vandam\u00e1l er \u00fev\u00ed fl\u00f3knara \u00fear sem flestar st\u00f6kkbreytingar eru meinlausar. \u00de\u00e6r hafa engin \u00e1hrif \u00e1 svipfari\u00f0, \u00fatlit e\u00f0a eiginleika f\u00f3lks. \u00c1 \u00feeim r\u00famleg 13 \u00e1rum sem li\u00f0in eru fr\u00e1 ra\u00f0greiningu erf\u00f0amengis mannsins hafa tug\u00fe\u00fasundir erf\u00f0amengja veri\u00f0 ra\u00f0greind. Flest mengin eru \u00far bakter\u00edum, en einnig hafa erf\u00f0amengi tilraunal\u00edfvera eins og \u00e1vaxtaflugna, gersveppa og vorskri\u00f0nabl\u00f3ms veri\u00f0 skr\u00e1\u00f0. Einnig hafa erf\u00f0amengi r\u00famlega 10.000 manns veri\u00f0 ra\u00f0greind og afhj\u00fapu\u00f0. G\u00f6gn um tilraunal\u00edfverur eru a\u00f0gengileg \u00ed opnum gagnagrunnum, en vegna pers\u00f3nuverndar eru n\u00e6stum \u00f6ll erf\u00f0amengi manna \u00ed loka\u00f0ri gagnav\u00f6rslu. Erf\u00f0amengja\u00f6ldin f\u00e6r\u00f0i okkur erf\u00f0amengi mannsins, inns\u00fdn \u00ed sj\u00fakd\u00f3ma og l\u00edffr\u00e6\u00f0i okkar en einnig gr\u00ed\u00f0arlega \u00feekkingu \u00e1 fj\u00f6lbreytileika d\u00fdra, plantna og \u00f6rvera. Samantekt:<\/p>\n