Leyndard\u00f3mar gena, bakter\u00eda og uppruna l\u00edfs<\/p>\n
Um R\u00e1\u00f0g\u00e1tu l\u00edfsins.<\/em><\/p>\n Birtist \u00ed n\u00e1tt\u00farufr\u00e6\u00f0ingnum 2015.<\/p>\n Ranns\u00f3knir \u00e1 erf\u00f0um, frumum og l\u00edfefnum g\u00e1tu af s\u00e9r sameindaerf\u00f0afr\u00e6\u00f0ina \u00e1 fyrstu \u00e1ratugum s\u00ed\u00f0ustu aldar. \u00c1 \u00feeim t\u00edma var Gu\u00f0mundur Eggertsson vi\u00f0 n\u00e1m \u00ed Kaupmannah\u00f6fn og kynntist ranns\u00f3knum sem l\u00f6g\u00f0u grunninn a\u00f0 sameindaerf\u00f0afr\u00e6\u00f0inni. Ranns\u00f3knir Gu\u00f0mundar snerust um gen bakter\u00eda og kerfin sem \u00fe\u00fd\u00f0a erf\u00f0at\u00e1knm\u00e1li\u00f0, og s\u00ed\u00f0ar um erf\u00f0ir hitak\u00e6rra bakter\u00eda. \u00cd n\u00fdlegu ritger\u00f0asafni, R\u00e1\u00f0g\u00e1ta l\u00edfsins<\/em>, fjallar Gu\u00f0mundur um nokkur lykilatri\u00f0i sameindaerf\u00f0afr\u00e6\u00f0innar og tilg\u00e1tur og ranns\u00f3knir \u00e1 uppruna l\u00edfsins. B\u00f3kin er tv\u00edskipt. \u00cd fyrstu fj\u00f3rum \u00fe\u00e1ttunum rekur Gu\u00f0mundur s\u00f6gu erf\u00f0afr\u00e6\u00f0innar, kynnir hugmyndir um geni\u00f0, segir fr\u00e1 erf\u00f0um bakter\u00eda og veira \u00feeirra og \u00fatsk\u00fdrir loks l\u00edkani\u00f0 um byggingu erf\u00f0aefnisins DNA. S\u00ed\u00f0an eru hugmyndir og tilraunir tengdar uppruna l\u00edfsins raktar \u00ed \u00feremur \u00fe\u00e1ttum. Umr\u00e6\u00f0an um uppruna l\u00edfs sprettur n\u00e1tt\u00farulega \u00far sameindaerf\u00f0afr\u00e6\u00f0inni og er samofin grunnatri\u00f0um hennar, enda \u00feurfa tilg\u00e1turnar a\u00f0 sk\u00fdra tilur\u00f0 gena, pr\u00f3t\u00edna og kerfa frumunnar. \u00cd lokin dregur Gu\u00f0mundur efni\u00f0 saman og tekst \u00e1 vi\u00f0 r\u00e1\u00f0g\u00e1tur l\u00edfsins.<\/p>\n Leyndard\u00f3mar gena og sameindaerf\u00f0afr\u00e6\u00f0i<\/strong><\/p>\n R\u00e9tt eins og erf\u00f0aefni\u00f0 er byggt upp af tveimur samofnum \u00fe\u00e1ttum eru r\u00e6tur sameindaerf\u00f0afr\u00e6\u00f0i a\u00f0skildar en samtvinna\u00f0ar, \u00far \u00f6rverufr\u00e6\u00f0i, erf\u00f0afr\u00e6\u00f0i, l\u00edfefnafr\u00e6\u00f0i og tilraunal\u00edffr\u00e6\u00f0i. Vi\u00f0fangsefni sameindaerf\u00f0afr\u00e6\u00f0i eru fj\u00f6lbreytt. H\u00fan ber upp spurningar \u00e1 bor\u00f0 vi\u00f0: Hvernig virkar fruman, hva\u00f0 er gen, hvernig hafa gen og breytingar \u00ed \u00feeim \u00e1hrif \u00e1 svipfar, hvernig ver\u00f0a st\u00f6kkbreytingar, og hv\u00ed hafa \u00f3l\u00edkar breytingar \u00ed geni missterk \u00e1hrif? V\u00edsindamenn me\u00f0 bakgrunn \u00ed \u00f3l\u00edkum fr\u00e6\u00f0um, jafnvel e\u00f0lisfr\u00e6\u00f0ingar og l\u00e6knar, t\u00f3kust \u00e1 vi\u00f0 st\u00f3rar spurningar og hj\u00e1lpu\u00f0ust a\u00f0 vi\u00f0 a\u00f0 svara \u00feeim. Framfarir \u00ed ranns\u00f3knum \u00e1 byggingu gensins ur\u00f0u fyrir tilstu\u00f0lan v\u00edsindamanna \u00e1 svi\u00f0i bakter\u00eduerf\u00f0afr\u00e6\u00f0i, en \u00feegar \u00fe\u00e1 rak \u00ed strand n\u00fdttust ni\u00f0urst\u00f6\u00f0ur fengnar me\u00f0 \u00f6\u00f0rum a\u00f0fer\u00f0um, svo sem l\u00edfefnafr\u00e6\u00f0i. Gu\u00f0mundur l\u00fdsir \u00feessu \u00ed samantekt kaflans um bakter\u00eduveirur.<\/p>\n \u00dea\u00f0 er l\u00edka \u00e1st\u00e6\u00f0a til a\u00f0 benda \u00e1 a\u00f0 margar af tilraunum bakter\u00eduveirusk\u00f3lans voru me\u00f0 s\u00e9rst\u00f6kum gl\u00e6sibrag. Flestar snertu \u00fe\u00e6r erf\u00f0ir veiranna. L\u00edfefnafr\u00e6\u00f0in var lengi vel sni\u00f0gengin en \u00fer\u00e1tt fyrir \u00fea\u00f0 fengust sk\u00fdrar ni\u00f0urst\u00f6\u00f0ur sem hlutu \u00feegar fram li\u00f0u stundir a\u00f0 h\u00f6f\u00f0a til l\u00edfefnafr\u00e6\u00f0inga og beinl\u00ednis kalla \u00e1 afskipti \u00feeirra. \u00deannig ur\u00f0u ranns\u00f3knir \u00e1 hinum \u00f6rsm\u00e1u bakter\u00eduveirum einn helsti hvati \u00feess samruna erf\u00f0afr\u00e6\u00f0ilegra og l\u00edfefnafr\u00e6\u00f0ilegra ranns\u00f3kna sem gengi\u00f0 hafa undir nafninu sameindal\u00edffr\u00e6\u00f0i. (68)<\/p><\/blockquote>\n \u00cd fyrsta kafla b\u00f3karinnar er kynnt geni\u00f0 og e\u00f0li erf\u00f0a. Hvernig flytjast eiginleikar fr\u00e1 foreldrum til afkv\u00e6ma? Hvers vegna eru afkv\u00e6mi stundum st\u00e6rri e\u00f0a rau\u00f0h\u00e6r\u00f0ari en foreldrarnir? Tilraunir Gregors Mendels (1822\u20131884) og fyrstu erf\u00f0afr\u00e6\u00f0inganna s\u00fdndu a\u00f0 einhverjar eindir fluttust fr\u00e1 foreldrum til afkv\u00e6ma. En \u00far hverju voru erf\u00f0aeindirnar sem Wilhelm Johannsen (1857\u20131927) kalla\u00f0i gen? \u00dea\u00f0 reyndist erfitt a\u00f0 finna byggingarefni gensins og enn \u00ed dag er erfitt a\u00f0 rannsaka virkni \u00feeirra. \u00cd \u00f6\u00f0rum og \u00feri\u00f0ja kafla b\u00f3karinnar rekur Gu\u00f0mundur s\u00f6gu ranns\u00f3kna \u00e1 erf\u00f0um bakter\u00eda og veira \u00feeirra. Grundvallarl\u00f6gm\u00e1l erf\u00f0a afhj\u00fapu\u00f0ust me\u00f0 ranns\u00f3knum \u00e1 pl\u00f6ntum og d\u00fdrum. Fyrstu erf\u00f0afr\u00e6\u00f0ingarnir efu\u00f0ust um a\u00f0 bakter\u00edur lytu \u00feeim l\u00f6gm\u00e1lum, e\u00f0a t\u00f6ldu a\u00f0 erf\u00f0ir \u00feeirra v\u00e6ru annarskonar en st\u00e6rri l\u00edfvera. \u201eBakter\u00edur voru lengi utangar\u00f0s \u00ed erf\u00f0afr\u00e6\u00f0inni,\u201c segir Gu\u00f0mundur (35). \u00de\u00e6r efasemdir voru r\u00e6kilega afsanna\u00f0ar. Sm\u00e1s\u00e6ir sveppir og bakter\u00edur reyndust hin heppilegustu tilraunad\u00fdr, uxu hratt, voru sparneytin, \u00feoldu frystingu og m\u00e1tti hreinr\u00e6kta. Me\u00f0 \u00feynningum og strikunum var h\u00e6gt a\u00f0 einangra staka stofna, sem r\u00e6ktu\u00f0ust af einni einustu bakter\u00edu \u2013 af \u00fev\u00ed a\u00f0 bakter\u00edur vaxa kynlaust. Einnig fundust fr\u00e1vik, stofnar \u00f6rvera sem s\u00fdndu s\u00e9rst\u00f6k einkenni. \u00der\u00e1tt fyrir kynlausar tilhneigingar bakter\u00eda reyndust \u00fe\u00e6r heppilegar fyrir erf\u00f0afr\u00e6\u00f0ilegar ranns\u00f3knir. M\u00f6gulegt var a\u00f0 blanda saman stofnum og finna blendinga. Miklu m\u00e1li skiptir a\u00f0 bakter\u00edur m\u00e1 r\u00e6kta \u00ed gr\u00ed\u00f0arlegu magni. Gu\u00f0mundur rekur fr\u00e1b\u00e6rlega hvernig \u201ekynl\u00edf\u201c bakter\u00eda og veira afhj\u00fapa\u00f0i lykilatri\u00f0i erf\u00f0afr\u00e6\u00f0innar. Eins og \u00e1\u00f0ur sag\u00f0i n\u00e1\u00f0u erf\u00f0afr\u00e6\u00f0ingar og l\u00edfefnafr\u00e6\u00f0ingar ekki saman \u00ed upphafi. \u201e\u00dea\u00f0 var varla fyrr en me\u00f0 tilraunum Beadles og Tatums a\u00f0 \u00fe\u00e6r t\u00f3ku a\u00f0 n\u00e1lgast hvor a\u00f0ra,\u201c segir Gu\u00f0mundur (33). George W. Beadle (1903\u20131989) og Edward L. Tatum (1909\u20131975) ger\u00f0u merkar tilraunir \u00e1 bleika brau\u00f0sveppnum (Neurospora crassa<\/em>). \u201e\u00deeir f\u00e9lagar framk\u00f6llu\u00f0u \u00ed Neurospora<\/em> fj\u00f6lda st\u00f6kkbreytinga sem hindru\u00f0u l\u00edfefnafr\u00e6\u00f0ileg ferli og skilgreindu \u00e1hrif \u00feeirra me\u00f0 l\u00edfefnafr\u00e6\u00f0ilegum og erf\u00f0afr\u00e6\u00f0ilegum a\u00f0fer\u00f0um\u201c (33). Hreinr\u00e6kta\u00f0ar l\u00edfefnafr\u00e6\u00f0ilegar tilraunir voru einnig stunda\u00f0ar. Hluti frumu e\u00f0a veiru var einangra\u00f0ur, og virknin k\u00f6nnu\u00f0. L\u00edfefnafr\u00e6\u00f0ilegar a\u00f0fer\u00f0ir virka vel fyrir st\u00f6\u00f0ugar st\u00f3rsameindir en s\u00ed\u00f0ur fyrir \u00f3st\u00f6\u00f0ugar afur\u00f0ir e\u00f0a pr\u00f3t\u00edn sem l\u00edfverur framlei\u00f0a \u00ed litlu magni e\u00f0a vi\u00f0 s\u00e9rstakar a\u00f0st\u00e6\u00f0ur.<\/p>\n \u00cd l\u00edffr\u00e6\u00f0i sem \u00f6\u00f0rum v\u00edsindum byggjast framfarir oft \u00e1 \u00fev\u00ed a\u00f0 v\u00edsindamennirnir finni heppileg kerfi. Mendel nota\u00f0i ertur. Frumkv\u00f6\u00f0lar sameindaerf\u00f0afr\u00e6\u00f0i notu\u00f0u \u00f6rverur og veirur sem s\u00fdktu \u00fe\u00e6r. Gu\u00f0mundur \u00fatsk\u00fdrir hvers vegna bakter\u00eduveirur reyndust svo vel til \u00feessara ranns\u00f3kna. Bakter\u00edur fj\u00f6lga s\u00e9r mj\u00f6g hratt, E. coli<\/em> skiptir s\u00e9r \u00e1 u.\u00fe.b. 25 m\u00edn\u00fatum, og veirurnar hafa einnig stuttan l\u00edft\u00edma. Mikilv\u00e6gast er a\u00f0 s\u00fdkja m\u00e1 gerla me\u00f0 tveimur st\u00f6kkbreyttum veirustofnum og meta t\u00ed\u00f0ni endurr\u00f6\u00f0unar \u00e1 milli gena og innan . \u00deannig fundust til d\u00e6mis gen sem stj\u00f3rnu\u00f0u s\u00fdkih\u00e6fni veirunnar. Ranns\u00f3knir \u00e1 bakter\u00eduveirum og efnaskiptum bakter\u00eda afhj\u00fapu\u00f0u l\u00f6gm\u00e1l genastj\u00f3rnunar. Gu\u00f0mundur minnir okkur \u00e1 mikilv\u00e6gi gerlanna:<\/p>\n Til \u00e1r\u00e9ttingar \u00e1 \u00fev\u00ed hve E. coli <\/em>n\u00fdttist vel til undirst\u00f6\u00f0uranns\u00f3kna m\u00e1 nefna a\u00f0 \u00e1 \u00e1runum 1959 til 1978 hlutu ekki f\u00e6rri en 10 v\u00edsindamenn N\u00f3belsver\u00f0laun fyrir ranns\u00f3knir \u00e1 erf\u00f0um e\u00f0a efnaferlum bakter\u00edunnar og veira hennar. En eftir 1980 \u00feegar a\u00f0fer\u00f0ir l\u00edft\u00e6kninnar h\u00f6f\u00f0u komi\u00f0 til s\u00f6gunnar t\u00f3k \u00e1hugi manna a\u00f0 beinast \u00e6 meir a\u00f0 heilkj\u00f6rnungum, a\u00f0 genum \u00feeirra og \u00feroskaferlum. \u00c1rangurinn l\u00e9t ekki \u00e1 s\u00e9r standa. Miklar ranns\u00f3knir eru samt enn stunda\u00f0ar \u00e1 bakter\u00edum \u00fe\u00f3tt bl\u00f3maskei\u00f0 bakter\u00eduerf\u00f0afr\u00e6\u00f0innar s\u00e9 li\u00f0i\u00f0. \u00dea\u00f0 er vafi\u00f0 \u00e6vint\u00fdralj\u00f3ma, ekki s\u00edst \u00ed augum \u00feeirra sem \u00fear voru \u00fe\u00e1tttakendur. (51)<\/p>\n Ein helsta r\u00e1\u00f0g\u00e1ta s\u00ed\u00f0ustu aldar var: Hva\u00f0 er erf\u00f0aefni\u00f0? \u00cd fj\u00f3r\u00f0a kafla b\u00f3karinnar segir fr\u00e1 leitinni a\u00f0 erf\u00f0aefninu og hvernig bygging \u00feess var afhj\u00fapu\u00f0. Gu\u00f0mundur l\u00fdsir \u00fev\u00ed hvernig tilraunir s\u00fdndu fram \u00e1 efnainnihald kjarns\u00fdrunnar DNA. H\u00fan samanstendur af fj\u00f3rum ger\u00f0um basa, sem kallast A, C, G og T. Fyrst var \u00e1lykta\u00f0 ranglega a\u00f0 basarnir v\u00e6ru \u00ed s\u00f6mu hlutf\u00f6llum og alltaf \u00ed s\u00f6mu r\u00f6\u00f0. Efni me\u00f0 sl\u00edka eiginleika gagnast ekki sem uppl\u00fdsingageymsla. L\u00edfefnafr\u00e6\u00f0ingurinn Erwin Chargaff (1905\u20132002) afsanna\u00f0i \u00feessa hugmynd og s\u00fdndi a\u00f0 hlutf\u00f6ll basanna eru ekki j\u00f6fn \u00ed \u00f6llum l\u00edfverum. Hann s\u00fdndi einnig a\u00f0 hlutf\u00f6ll A- og T-basa og C- og G-basa haldast \u00ed hendur, sem bendir til einhverra tengsla \u00feeirra \u00e1 milli. Tilraunir Alfreds Hersheys (1908\u20131997) og M\u00f6rthu Chase (1927\u20132003) bentu sterklega til \u00feess a\u00f0 erf\u00f0aefni\u00f0 v\u00e6ri DNA, en enginn vissi byggingu \u00feess. Margir virtir v\u00edsindamenn reyndu a\u00f0 sm\u00ed\u00f0a l\u00edkan sem g\u00e6ti \u00fatsk\u00fdrt byggingu og eiginleika DNA. Francis Crick (1916\u20132004) og James Watson t\u00f3ku h\u00f6ndum saman upp \u00far 1950, og me\u00f0 nokkrar grunnreglur a\u00f0 vopni, frj\u00f3tt \u00edmyndunarafl og hli\u00f0sj\u00f3n af myndum Rosalindu Franklin (1920\u20131958) t\u00f3kst \u00feeim a\u00f0 r\u00e1\u00f0a g\u00e1tuna. DNA er \u00fer\u00e1\u00f0ur, mynda\u00f0ur \u00far tveimur \u00fe\u00e1ttum \u00fear sem basarnir sn\u00faa inn \u00ed mi\u00f0juna og parast (A vi\u00f0 T og G vi\u00f0 C). Byggingin b\u00e6\u00f0i verndar uppl\u00fdsingarnar og b\u00fd\u00f0ur einfalda lei\u00f0 til afritunar. \u00de\u00e6ttirnir eru a\u00f0skildir og hvor um sig nota\u00f0ur sem forskrift a\u00f0 n\u00fdjum \u00fe\u00e6tti.<\/p>\n R\u00e1\u00f0g\u00e1tan um uppruna l\u00edfsins<\/strong><\/p>\n Sv\u00f6r gle\u00f0ja en \u00f3leystar r\u00e1\u00f0g\u00e1tur eru enn meira spennandi. Seinni hluti b\u00f3karinnar fjallar um st\u00e6rstu r\u00e1\u00f0g\u00e1tu l\u00edffr\u00e6\u00f0innar, uppruna l\u00edfs. \u00d6nnur \u00f6ndvegisb\u00f3k Gu\u00f0mundar, Leitin a\u00f0 uppruna l\u00edfs<\/em>,[1]<\/a> fjallar einnig um \u00feetta efni. \u00cd R\u00e1\u00f0g\u00e1tunni<\/em> kafar hann \u00fdtarlegar \u00ed vissa \u00fe\u00e6tti. Fyrst r\u00e6\u00f0ir hann ranns\u00f3knir Louis Pasteurs (1822\u20131895) og samt\u00edmamanna \u00e1 r\u00e1\u00f0g\u00e1tu \u00feeirra aldar: Kviknar l\u00edf af sj\u00e1lfu s\u00e9r?<\/em> Tilg\u00e1ta sem F\u00e9lix A. Pouchet (1800\u20131872) a\u00f0hylltist var s\u00fa a\u00f0 l\u00edf kvikna\u00f0i au\u00f0veldlega, jafnvel yfir helgi \u00ed hr\u00e6i. Tilg\u00e1ta Pasteurs var a\u00f0 l\u00edf sprytti alltaf af l\u00edfi. Eins og oft \u00ed s\u00f6gu v\u00edsindanna er au\u00f0velt a\u00f0 vera vitur eftir \u00e1, en umfj\u00f6llun Gu\u00f0mundar er n\u00e6rg\u00e6tin og ma\u00f0ur \u00e1 au\u00f0velt me\u00f0 a\u00f0 skilja \u00f3vissuna sem v\u00edsindamenn \u00feessa t\u00edma st\u00f3\u00f0u frammi fyrir. \u00deegar tekist er \u00e1 vi\u00f0 st\u00f3rar spurningar er ekki endilega lj\u00f3st hva\u00f0 eru sta\u00f0reyndir og hva\u00f0 mislukka\u00f0ar tilraunir. \u00dev\u00ed er f\u00f3lki sannarlega vorkunn a\u00f0 eiga b\u00e1gt me\u00f0 a\u00f0 greina sannindi fr\u00e1 bulli, jafnt v\u00edsindam\u00f6nnum sem leikm\u00f6nnum. R\u00e1\u00f0g\u00e1tan um kviknun l\u00edfs var leyst me\u00f0 snilldarlegum tilraunum fyrstu \u00f6rverufr\u00e6\u00f0inganna. L\u00edf getur l\u00edf, \u00fea\u00f0 kviknar ekki h\u00e9r og \u00fear af sj\u00e1lfu s\u00e9r. R\u00e9tt eins og Darwin komst a\u00f0 er \u00fea\u00f0 \u00fe\u00f3 svo a\u00f0 ef l\u00edf sprettur af l\u00edfi og h\u00e6gt er a\u00f0 rekja alla til forf\u00f6\u00f0ur, \u00fe\u00e1 hlj\u00f3ta allir forfe\u00f0urnir a\u00f0 eiga forfe\u00f0ur. D\u00fdpst \u00ed aldanna r\u00e1s \u00e1 l\u00edf \u00e1 j\u00f6r\u00f0inni einn sameiginlegan forf\u00f6\u00f0ur.<\/p>\n Um tilraunir til a\u00f0 finna uppruna \u00feessa forf\u00f6\u00f0ur er fjalla\u00f0 um \u00ed sj\u00f6tta \u00fe\u00e6tti, \u201eSkref \u00e1 lei\u00f0 til l\u00edfs\u201c. Samofin er spurningin: Hva\u00f0 er l\u00edf? <\/em>Hvernig skilgreinum vi\u00f0 l\u00edf og hva\u00f0a einkenni hafa l\u00edfverur? L\u00edfverur geta af s\u00e9r a\u00f0rar l\u00edfverur og \u00fer\u00f3ast. L\u00edfverur samanstanda af st\u00f3rsameindum, kolefnisfj\u00f6lli\u00f0um og \u00f6\u00f0rum grunneiningum. Sumar \u00feessara eininga finnast \u00ed dau\u00f0ri n\u00e1tt\u00faru e\u00f0a jafnvel \u00e1 loftsteinum. En hva\u00f0 leiddi til \u00feess a\u00f0 \u00ed samsafni dau\u00f0ra efna \u00ed vatnslausn kvikna\u00f0i l\u00edf? Gu\u00f0mundur rekur hugmyndir manna um \u00feessa spurningu og tilraunir sem ger\u00f0ar voru til a\u00f0 varpa lj\u00f3si \u00e1 vandann. Erf\u00f0ir og \u00fer\u00f3un einkenna allar l\u00edfverur og \u00fev\u00ed telja sumir a\u00f0 uppruni eftirmyndunar s\u00e9 uppruni l\u00edfs. A\u00f0rir segja a\u00f0 l\u00edfverur \u00feurfi orku, og \u00fev\u00ed hlj\u00f3ti uppruninn a\u00f0 hafa veri\u00f0 \u00ed efnaskiptum. Enn a\u00f0rir benda \u00e1 a\u00f0 l\u00edf s\u00e9 ramma\u00f0 inn \u00ed frumur og \u00e1lykta a\u00f0 fyrstu frumuhimnurnar hafi veri\u00f0 lykilinn a\u00f0 l\u00edfinu. Gu\u00f0mundur \u00fatsk\u00fdrir \u00feessar hugmyndir \u00e1g\u00e6tlega, en leggur einnig \u00e1herslu \u00e1 a\u00f0 engin lei\u00f0 s\u00e9 a\u00f0 vita hva\u00f0 ger\u00f0ist fyrst e\u00f0a hver hafi veri\u00f0 r\u00f6\u00f0 vi\u00f0bur\u00f0anna. Sannarlega er h\u00e6gt a\u00f0 \u00edmynda s\u00e9r mun lausbeisla\u00f0ra l\u00edf en n\u00fa \u00feekkist, \u00fear sem efnaskipti \u00ed losaralegri frumefnas\u00fapu hafi loks leitt til eftirmyndandi eininga. Jafnvel m\u00e1 hugsa s\u00e9r a\u00f0 \u00feetta hafi gerst \u00ed hverum \u00fear sem voru \u00a0heppilegir steinar e\u00f0a vikurmolar me\u00f0 h\u00f3lf fyrir einskonar frum-frumur. Ein hressilegasta tilg\u00e1tan er s\u00fa a\u00f0 \u00ed \u00e1rdaga hafi l\u00edfi\u00f0 veri\u00f0 \u00e1 RNA-formi. Samkv\u00e6mt henni voru l\u00edfverur ekki me\u00f0 DNA fyrir erf\u00f0aefni og pr\u00f3t\u00edn sem framkv\u00e6mendur, heldur sinnti RNA b\u00e1\u00f0um hlutverkum. RNA er sannarlega st\u00f3rbrotin sameind og kannski voru sl\u00edkar sj\u00e1lfeftirmyndandi RNA-sameindir lykilskref \u00e1 lei\u00f0 til l\u00edfs (eins og vi\u00f0 \u00feekkjum \u00fea\u00f0). Framhaldi\u00f0 er betur \u00feekkt. Vi\u00f0 vitum a\u00f0 fram spruttu fj\u00f6lm\u00f6rg kerfi frumna sem st\u00fdra eftirmyndun, framlei\u00f0slu pr\u00f3t\u00edna, seytingu efna o.s.frv. Jafnvel uppruni heilkjarnal\u00edfvera er \u00fe\u00f3 hulinn t\u00f6luver\u00f0ri \u00f3vissu, og nokkrar kenningar \u00e1 lofti. \u00dea\u00f0 er \u00fev\u00ed skiljanlegt a\u00f0 okkur skorti vitneskju um fyrstu skref l\u00edfsins.<\/p>\n \u00cd n\u00e6sts\u00ed\u00f0asta hluta b\u00f3karinnar r\u00e6\u00f0ir Gu\u00f0mundur hugmyndina um l\u00edf utan \u00far geimnum. Vi\u00f0urkennt er a\u00f0 l\u00edfi\u00f0 \u00e1 j\u00f6r\u00f0inni s\u00e9 af einum mei\u00f0i. En spratt l\u00edfi\u00f0 fram h\u00e9r e\u00f0a kom \u00fea\u00f0 annars sta\u00f0ar fr\u00e1? Tilg\u00e1tur af \u00feessu tagi hafa a\u00f0dr\u00e1ttarafl, sem stafar a\u00f0 einhverju leyti af \u00fev\u00ed hversu brj\u00e1l\u00e6\u00f0islegar \u00fe\u00e6r eru. Sl\u00edkum huglei\u00f0ingum fylgir sami kitlandi \u00e6singurinn og \u00feegar ma\u00f0ur stendur \u00e1 br\u00fan hengiflugs. Sumum finnst mj\u00f6g \u00f3l\u00edklegt a\u00f0 l\u00edf ver\u00f0i til \u00far dau\u00f0um sameindum, og \u00fev\u00ed l\u00edklegra a\u00f0 l\u00edfi\u00f0 hafi borist hinga\u00f0 me\u00f0 loftsteinum e\u00f0a geimryki. L\u00edf af \u00feessu tagi hl\u00fdtur a\u00f0 vera einfalt, l\u00edklega einhverskonar bakter\u00edur. Vegna \u00f3m\u00e6ldra v\u00eddda geimsins \u00feyrftu \u00fe\u00e6r a\u00f0 vera \u00e1 dvalarformi, \u00ed b\u00fdsna langan t\u00edma. \u00cd \u00feessu samhengi sprettur fram \u00f6nnur spurning. Hversu miklar l\u00edkur eru \u00e1 l\u00edfi \u00e1 \u00f6\u00f0rum pl\u00e1netum? Gu\u00f0mundur segir:<\/p>\n Tali\u00f0 er a\u00f0 \u00ed Vetrarbrautinni s\u00e9u nokkur \u00fe\u00fasund milljar\u00f0ar s\u00f3lstjarna og n\u00fdlegar ranns\u00f3knir benda til \u00feess a\u00f0 reikistj\u00f6rnur sem ganga umhverfis \u00fe\u00e6r s\u00e9u s\u00ed\u00f0ur en svo sjaldg\u00e6far. Fr\u00e1 \u00fev\u00ed um mi\u00f0jan 10. \u00e1ratug s\u00ed\u00f0ustu aldar til apr\u00edlm\u00e1na\u00f0ar 2014 hefur stj\u00f6rnufr\u00e6\u00f0ingum tekist a\u00f0 greina um 1800 reikistj\u00f6rnur \u00ed 1105 s\u00f3lkerfum sem \u00f6ll eru tilt\u00f6lulega n\u00e1l\u00e6gt j\u00f6r\u00f0u. (134)<\/p><\/blockquote>\n Og \u00e1lyktar s\u00ed\u00f0an:<\/p>\n Telja m\u00e1 v\u00edst a\u00f0 s\u00f3lkerfi samb\u00e6rileg vi\u00f0 okkar hafi geta\u00f0 myndast nokkrum millj\u00f6r\u00f0um \u00e1ra fyrr. \u00dea\u00f0 er \u00fev\u00ed hugsanlegt a\u00f0 l\u00edf hafi n\u00e1\u00f0 a\u00f0 \u00fer\u00f3ast \u00ed alheimi millj\u00f6r\u00f0um \u00e1ra \u00e1 undan l\u00edfi jar\u00f0ar. Hvort \u00fea\u00f0 hefur borist um \u00f3rav\u00edddir geimsins til jar\u00f0ar er hins vegar spurning sem enn eru engin t\u00f6k \u00e1 a\u00f0 svara. (bls. 134\u2013135)<\/p><\/blockquote>\n \u00cd s\u00ed\u00f0asta kafla b\u00f3karinnar fjallar Gu\u00f0mundur um nokkrar st\u00f3rar spurningar, svo sem um me\u00f0vitund. Hann segir:<\/p>\n Ma\u00f0urinn er ein af millj\u00f3num l\u00edfverutegunda sem byggja j\u00f6r\u00f0ina. Hann sver sig \u00ed \u00e6tt vi\u00f0 anna\u00f0 l\u00edf jar\u00f0ar en hann hefur s\u00e9rst\u00f6\u00f0u. Hann er eftir \u00fev\u00ed sem vi\u00f0 best vitum g\u00e6ddur me\u00f0vitund og h\u00e6fileikum til hugsunar \u00ed r\u00edkara m\u00e6li en a\u00f0rar l\u00edfverur...<\/p>\n [E]n hva\u00f0an kemur okkur me\u00f0vitundin? Hvert er e\u00f0li hennar og ors\u00f6k? Flestir v\u00edsindamenn munu tr\u00faa \u00fev\u00ed a\u00f0 me\u00f0vitundin eigi s\u00e9r efnislega sk\u00fdringu, a\u00f0 h\u00fan s\u00e9 \u00e1 einhvern h\u00e1tt sprottin af eiginleikum taugakerfisins. \u00deetta jafngildir \u00ed raun tr\u00fa \u00e1 sk\u00fdringarm\u00e1tt \u00feeirrar heimsmyndar sem v\u00edsindin hafa tileinka\u00f0 s\u00e9r s\u00ed\u00f0an \u00e1 d\u00f6gum Galileos. \u00de\u00f3 h\u00f6fum vi\u00f0 enn sem komi\u00f0 er alls enga efnislega sk\u00fdringu \u00e1 \u00fev\u00ed hvernig vi\u00f0 ver\u00f0um me\u00f0vitu\u00f0 um umhverfi okkar e\u00f0a hugsun. Hvernig getur hold og bl\u00f3\u00f0 eins og ma\u00f0urinn or\u00f0i\u00f0 me\u00f0vita\u00f0 um sj\u00e1lft sig? Vissulega h\u00f6fum vi\u00f0 fl\u00f3ki\u00f0 taugakerfi en hvernig skapar \u00fea\u00f0 okkur me\u00f0vitund? Hven\u00e6r \u00ed \u00fer\u00f3unars\u00f6gunni kom me\u00f0vitund fyrst fram? Varla er h\u00e6gt a\u00f0 efast um me\u00f0vitund d\u00fdra sem eru okkur hva\u00f0 skyldust, en hva\u00f0 me\u00f0 a\u00f0rar l\u00edfverur? Er me\u00f0vitund endilega tengd taugakerfinu? (158)<\/p><\/blockquote>\n \u00c1 s\u00ed\u00f0ustu \u00e1ratugum hafa taugal\u00edffr\u00e6\u00f0ingar og s\u00e1lfr\u00e6\u00f0ingar f\u00e6rst n\u00e6r sv\u00f6rum vi\u00f0 \u00feessum spurningum. \u00cd \u00feessu samhengi m\u00e1 einnig spyrja hversu vel vi\u00f0 skiljum e\u00f0li l\u00edfsins. Er til a\u00f0 mynda l\u00edklegt a\u00f0 n\u00fdjar uppg\u00f6tvanir kollvarpi vi\u00f0teknum hugmyndum um e\u00f0li l\u00edfsins? Gu\u00f0mundur spyr og r\u00e6\u00f0ir:<\/p>\n Er skilningur okkar \u00e1 l\u00edfinu or\u00f0inn \u00fea\u00f0 traustur a\u00f0 vi\u00f0 honum ver\u00f0i ekki hr\u00f3fla\u00f0 svo um muni? \u00deeir eru til sem halda \u00fev\u00ed fram a\u00f0 v\u00edsindaleg \u00feekking og skilningur s\u00e9 \u00f3\u00f0um a\u00f0 n\u00e1lgast endim\u00f6rk s\u00edn, en \u00e6ttum vi\u00f0 ekki a\u00f0 hinkra vi\u00f0 enn um stund \u00e1\u00f0ur en vi\u00f0 f\u00f6llumst \u00e1 \u00fea\u00f0? V\u00edsindin eru sk\u00f6punarferli \u00fear sem n\u00fd sj\u00f3narhorn koma st\u00f6\u00f0ugt fram og gera m\u00f6nnum kleift a\u00f0 spyrja n\u00fdrra spurninga og f\u00e1 sv\u00f6r vi\u00f0 \u00feeim. H\u00f6fum l\u00edka \u00ed huga a\u00f0 hinar merkustu uppg\u00f6tvanir hafa hinga\u00f0 til gjarna veri\u00f0 gersamlega \u00f3fyrirsj\u00e1anlegar. (262)<\/p><\/blockquote>\n M\u00e9r finnst sj\u00e1lfum l\u00edklegast a\u00f0 meginsto\u00f0ir l\u00edffr\u00e6\u00f0innar s\u00e9u or\u00f0nar sk\u00fdrar. Sannarlega eru tiltekin svi\u00f0 l\u00edffr\u00e6\u00f0innar traustari en \u00f6nnur, sem geyma \u00f3leystar \u00ferautir. Spyrja m\u00e1 hvar mestar l\u00edkur s\u00e9u \u00e1 umbyltingu. Er \u00fea\u00f0 til d\u00e6mis \u00ed erf\u00f0afr\u00e6\u00f0i, frumul\u00edffr\u00e6\u00f0i e\u00f0a atferlisfr\u00e6\u00f0i? Mig grunar a\u00f0 skipulagsstigin sem \u00f3l\u00edk svi\u00f0 l\u00edffr\u00e6\u00f0innar tilheyra hafi \u00e1hrif \u00e1 l\u00edkurnar \u00e1 byltingu. Erf\u00f0afr\u00e6\u00f0in er mitt fag og \u00ed \u00fev\u00ed eru undirst\u00f6\u00f0ul\u00f6gm\u00e1lin \u00e1 hreinu, svo sem bygging DNA og litninga, a\u00f0skilna\u00f0ur sams\u00e6tna, \u00f3h\u00e1\u00f0ar erf\u00f0ir litninga og endurr\u00f6\u00f0un. En \u00e1hrif genanna \u00e1 frumur, \u00feroskun, l\u00edfe\u00f0lisfr\u00e6\u00f0i og atferli eru mun verr skilgreind. \u00de\u00f3tt m\u00f6rg grundvallaratri\u00f0i s\u00e9u skilgreind \u00ed atferlisfr\u00e6\u00f0i \u00feykir m\u00e9r l\u00edklegra a\u00f0 \u00fear ver\u00f0i uppstokkun en \u00ed erf\u00f0afr\u00e6\u00f0i. \u00c1st\u00e6\u00f0an er alls ekki a\u00f0 atferlisfr\u00e6\u00f0in s\u00e9 \u00e1 einhvern h\u00e1tt \u00f3\u00e6\u00f0ri, heldur er h\u00fan \u00e1 h\u00e6rra skipulagsstigi og \u00fev\u00ed h\u00e1\u00f0 fleiri \u00fe\u00e1ttum. Atferli \u00fearf a\u00f0 l\u00fata l\u00f6gm\u00e1lum e\u00f0lisfr\u00e6\u00f0i, efnafr\u00e6\u00f0i, erf\u00f0afr\u00e6\u00f0i, frumul\u00edffr\u00e6\u00f0i, \u00feroskunar og l\u00edfe\u00f0lisfr\u00e6\u00f0ilegra kerfa, auk sinna eigin l\u00f6gm\u00e1la og au\u00f0vita\u00f0 \u00fer\u00f3unar. L\u00f6gm\u00e1l erf\u00f0a eru tj\u00f3\u00f0ru\u00f0 af l\u00f6gm\u00e1lum e\u00f0lisfr\u00e6\u00f0i, efnafr\u00e6\u00f0i og \u00fer\u00f3unar. Sannarlega v\u00e6ri forvitnilegt ef \u00feessi hugmynd v\u00e6ri r\u00f6ng. Hvort heldur er hefur Gu\u00f0mundur a\u00f0 \u00f6llum l\u00edkindum r\u00e9tt fyrir s\u00e9r, l\u00edffr\u00e6\u00f0ingar munu hafa \u00e6rinn starfa um \u00f3komna framt\u00ed\u00f0.<\/p>\n R\u00e1\u00f0g\u00e1ta l\u00edfsins <\/em>er sk\u00fdr og skemmtileg b\u00f3k. \u00dear eru kynnt forvitnileg fyrirb\u00e6ri, s\u00f6g\u00f0 athyglisver\u00f0 og au\u00f0ug saga og spurt st\u00f3rra spurninga. Sumum hefur veri\u00f0 svara\u00f0 en a\u00f0rar b\u00ed\u00f0a enn svars. Ef til vill eftir \u00fe\u00ednu framlagi, hugmynd e\u00f0a tilraun. \u00c9g hvet f\u00f3lk til a\u00f0 lesa b\u00f3kina og r\u00e6\u00f0a efni hennar vi\u00f0 sem flesta, jafnvel \u00ed fermingarveislum e\u00f0a str\u00e6t\u00f3. R\u00e1\u00f0g\u00e1tur l\u00edfsins eru blessun.<\/p>\n Arnar P\u00e1lsson, erf\u00f0afr\u00e6\u00f0ingur vi\u00f0 H\u00e1sk\u00f3la \u00cdslands.<\/p>\n <\/p>","protected":false},"excerpt":{"rendered":" Leyndard\u00f3mar gena, bakter\u00eda og uppruna l\u00edfs Um R\u00e1\u00f0g\u00e1tu l\u00edfsins. Birtist \u00ed n\u00e1tt\u00farufr\u00e6\u00f0ingnum 2015. Ranns\u00f3knir \u00e1 erf\u00f0um, frumum og l\u00edfefnum g\u00e1tu af s\u00e9r sameindaerf\u00f0afr\u00e6\u00f0ina \u00e1 fyrstu \u00e1ratugum s\u00ed\u00f0ustu aldar. \u00c1 \u00feeim t\u00edma var Gu\u00f0mundur Eggertsson vi\u00f0 n\u00e1m \u00ed Kaupmannah\u00f6fn og kynntist … Halda \u00e1fram a\u00f0 lesa \n