Zomwe Biology Yamoyo Imanyalanyaza Mukusintha

Ndikupepesa chifukwa chamutu wankhaniyi ku gulu la R.E.M., ngakhale zili bwino kuti atchule dzina lawo mgulu lofunika kwambiri la tulo.

Katswiri wa sayansi ya zamankhwala ku Spain a Victor de Lorenzo (2014; munyuzipepalayi Zosangalatsa ) wanena kuti chiphunzitso chapakati cha biology ya molekyulu, "DNA imapanga RNA kupanga mapuloteni" (tsamba 226) imanyalanyaza kufunikira kwa "kagayidwe kodzikonda." Chotsatirachi ndi lingaliro lake loti kusinthika kwakukulu kwa zinthu zomwe zili ndi DNA sikungobwereza ndikukula kwa DNA yawo m'malo awo koma kuwunika ndikugwiritsa ntchito malo awo amankhwala. Komwe kudalitsidwako komwe kumachitika komanso kugwiritsa ntchito mankhwala opititsa patsogolo kagayidwe kake kumathandizira kutsimikizira kupititsa patsogolo njira zawo zamagetsi, zomwe zimathandizira kutsimikiza kuti zingabwerenso ndikukula kwa DNA yawo mu jini.

Komabe, zodabwitsazi zimadza: Cholinga cha biology ya maselo pa DNA chikuwoneka kuti chili ndi cholakwika mwina chifukwa cha chisinthiko. DNA itha kuwonedwa ngati kusintha kwa zingwe ziwiri za RNA, chifukwa RNA ndi DNA sizinasinthe mosiyana. Chifukwa chake, RNA iyenera kuti idatsogola DNA munthawi yosintha. Lingaliro lomalizirali limadziwika kuti RNA World Hypothesis, ndiye kuti, m'maselo akulu, omwe amadziwika kuti ma prokaryotes, RNA yokha ndi yomwe imasunga zidziwitso zamtunduwu ndikuwongolera momwe amathandizira. Chosangalatsa ndichakuti, umboni wazakale zakale ukuwoneka kuti ukuwonetsa kuti ma prokaryote adawoneka pafupifupi zaka 3.9 biliyoni zapitazo. Chosangalatsanso ndichakuti RNA idapitilizabe, kotero lingaliro loti lingafanane ndi "zakale" zoyambira moyo ndilopatsa chidwi. Ndimaonanso kuti ma prokaryotes amaganiza zodzetsa nkhawa popeza dziko lenilenili lili ndi zaka 4.567 biliyoni zokha. Chifukwa chake, maselo ovuta modabwitsa, okhala ndi makoma am'mbali ozungulira cytoplasm, RNA, zolandirira mankhwala ndi ma mechanical receptors (kuti azindikire zopinga), ndi flagella yomwe imawongolera mayendedwe opita ndi kutali ndi mankhwala ndi zinthu anali atakhala kale zaka theka la biliyoni (kapena ) dziko litakhazikika! Ngakhale zaka theka la biliyoni zingawoneke ngati nthawi yayitali, mwina sizingaperekedwe m'mbiri yazaka mabiliyoni ambiri padziko lapansi. Ndiye zinatheka bwanji kuti chisinthiko chichitike m'nthawi yochepa chonchi? Lingaliro limodzi lotopetsa ndiloti ma prokaryotes sanasinthe ... padziko lapansi. Ndiye kuti, adachokera ku comet kapena meteorite. Zachidziwikire kuti izi zimabweretsa funso kuti zamoyo zovuta bwanji izi zidayamba ndikumangirizidwa mu comet kapena meteorite ndipo zinali zikhalidwe ziti zoyambirira pakusintha kwawo kulikonse komwe adasinthika?

Koma kubwerera ku dziko lonse lapansi la RNA: RNA imadziwika kuti imakhala ndi ma nucleotide anayi okha, Adenine (A), Uracil (U), Cytosine (C), Guanine (G) [zindikirani: mu DNA, uracil amakhala thymine (T), kudzera mu njira ya methylation]. Komabe, RNA sinatuluke, yakula bwino, ndi ma nucleotide anayi okha, monga Athena wochokera pamphumi pa Zeus!

Zikuwoneka kuti ngakhale akatswiri a RNA World amanyalanyaza kuti payenera kukhala panali malo a RNA asanafike omwe amakhala ndi mankhwala ofunikira kuti apange ma nucleotide osiyanasiyana. Kuphatikiza apo, kuphatikizana ndi kusakwanira kwa mankhwala ndi mamolekyulu ziyenera kuti zidakhazikitsidwa ndi zomangira zowonjezerapo zamagetsi. Chifukwa chake, mamolekyulu oyambilira omwe amadzipangira okha omwe amapanga pre-nucleotide, ndi ma nucleotide anayi omaliza omwe adapanga zingwe zoyambirira za RNA anali atakakamizidwa kale ndimankhwala oyambilira a atomiki.

Apa pakubuka funso lina lofunika: kodi zisankho zoyambilira izi zidatengera kusankha kwa Darwin? Ngati kuphunzira kosagwirizana, komwe kumakhala kuzolowera komanso kulimbikitsa, ndikokulira kwakusintha kuposa kuphunzira kophatikizana (koyambirira komanso kogwirira ntchito), kodi maphunziro osakhala oyanjana nawo ndiwo anali maziko ofufuza ndi kugwiritsa ntchito malo owoneka bwino amankhwala?

Ngakhale de Lorenzo adangoyang'ana kwambiri pa DNA, mwina lingaliro lodzikonda lomwe limagwiritsidwa ntchito limagwiritsidwa ntchito pazoyambitsa zamankhwala za nucleotide ndi mawonekedwe a nucleotide omwe sanapangitse "anayi omaliza" omwe adafotokozera RNA. Zitha kuyerekezera kuti mitundu ina iyi ya ma nucleotide ndi mamolekyulu ena ovuta mu pre-RNA padziko lapansi adalephera kupitilira ndikukula chifukwa sanathe kufufuza ndikugwiritsa ntchito malo awo amankhwala komanso ma nucleotide anayi omaliza. Chifukwa chake, kuchokera pakusintha kwazinthu, chiphunzitso chachikulu cha biology ya ma molekyulu (ma DNA ma RNA, ma RNA amalemba mapuloteni) zikuwoneka ngati zonyalanyaza kuti 1) RNA iyenera kuti idalipo DNA, 2) ma cell a pre-cell a ma nucleotide anali okhudzana ndi mankhwala ndi atomiki , 3) payenera kuti panali ma nucleotide ena asanachitike komanso munthawi ya anayi omaliza, 4) kuthekera kofufuza ndikugwiritsa ntchito malo am'magulu am'magulu atsopano kunali koyendetsa bwino pakusintha kwawo konse, ndipo 5) kufufuzaku akhala akugonjera masankhidwe achilengedwe a Darwin ndipo mwina adachititsidwa ndi mitundu iwiri yophunzirira yosagwirizana, mwachitsanzo, chizolowezi ndikulimbikitsa (kapena machitidwe a atomiki amitundu iyi yamaphunziro). Chifukwa chake, zitha kukhala zofunikira pakuwunika kwa mamolekyulu amitundu yatsopano kuti anyalanyaze zosafunikira (chizolowezi) ndikumvetsetsa zomwe zingachitike (kulimbikitsa).

Pulofesa Frederick L. Coolidge ndi director director wa Center for Cognitive Archaeology ku University of Colorado, Colorado Springs. Center imapereka maphunziro a pa intaneti ndi satifiketi mu Cognitive Archaeology. Lumikizanani [email protected].