Kuguquka okuzenzekelayo: ngezigaba, izimbangela, izibonelo

Lokho okubizwa ngokuthi kuguquka nokuguqulwa? Uma igama elithi ukudluliswa ngolimi etholakalayo, kuba namaphutha zemvelo ezenzeka phakathi nokuxhumana nesidoda okunikelwe kusukela imvelo yangaphakathi kanye / noma yangaphandle. ukuguqulwa kwezakhi zofuzo okunjalo ngokuvamile ngephutha. Basuke ebonwe ubulili, futhi ezinye emangqamuzaneni omzimba.

Exogenous kubangela ukushintsha izakhi zofuzo okuqondiswa

ukuguquka kwezakhi zofuzo okuzenzekelayo singenzeka ngaphansi kwethonya amakhemikhali ngemisebe, ngaphansi isenzo lokushisa eliphezulu kakhulu noma eliphansi, emoyeni mncane noma umfutho ophakeme.

Unyaka ngamunye, umuntu udla mayelana omunye kwabayishumi uyakujabulela ionizing emisebeni esiba emisebeni yangemuva zemvelo. Leli nani lihlanganisa gamma kwemisebe emhlabeni nengaphakathi ama-solar wind, izakhi radioactive, lulele ukushuba kuqweqwe ziyoncibilika emkhathini. Umthamo okuholela futhi incike lapho abantu. Ikota zonke izinto ngokuguqula izakhi, nokuguqulwa kwenzeka iphutha lokhu isici.

Yelanga, okuhlukile kokuvamile, kunendima ethile ekugcineni ingane okubangela ukulimala kwe-DNA, njengoba abakwazi ukungena ngokujule ngokwanele emzimbeni womuntu. Kodwa isikhumba ngokuvamile uhlushwa insolation ngokweqile (i-melanoma nezinye izinhlobo zomdlavuza). Nokho, izinto eziphilayo owumphumela namagciwane liguquke lapho zihlatshwa yilanga.

Too lokushisa eliphezulu kakhulu noma eliphansi kakhulu kungabangela izinguquko eziyisisekelo zofuzo.

Endogenous kubangela ukushintsha izakhi zofuzo okuqondiswa

Izizathu eziyinhloko ngenxa lapho kuguquka nokuguqulwa singenzeka, yizici endogenous. Lezi zihlanganisa ohlangothini-imikhiqizo umzimba, namaphutha phakathi ukufanisana, ukulungisa kanye recombination, nabanye.

1. Ukuhluleka ukufanisana:
   - ukuhwebelana okuvele inversions elisekela nitrogen;
   - Ukufakwa okungafanele ka-nucleotide ka polymerases DNA amaphutha;
   - chemical esikhundleni ka-nucleotide, ezifana-guanine ne-cytosine-ukuba i-adenine-guanine.
2. Iphutha umsebenzi wokuvuselela izakhiwo:
   - ukuguquka kwezakhi zofuzo e izakhi zofuzo ezibangela ukukhanda of izingxenye ngazinye Strand DNA ngemva break yabo ngaphansi kwethonya iziphi izici zangaphandle.
3. Izinkinga recombination:
   - ukwehluleka inqubo crossover ngesikhathi meiosis futhi mitosis yi imvula futhi isandiso kusuka izisekelo.

Lawa izici eziyinhloko okubangela ukuguquka kwezakhi zofuzo nokuguqulwa. Izimbangela ukwehluleka kungaba ukwenza kusebenze mutator izakhi zofuzo kanye ukuguqulwa ephephile chemical compounds ku metabolites bakhuthele ezithinta kuyi-nucleus yengqamuzana. Ngaphezu kwalokho, kukhona izinto ezihlelekile. Lezi zihlanganisa okuphindayo nucleotide ukulandelanisa eduze wesifunda indawo ukulungiswa, khona ezengeziwe izifunda DNA afana e isakhiwo ufuzo, kanye izakhi ezithathekayo zofuzo.

pathogenesis ukuguquka kwezakhi zofuzo

kuguquka okuzenzekelayo kwenzeka ngenxa umthelela zonke lezi zici ezithinta, ndawonye noma ngokuhlukile kwenkathi ethile ekuphileni esitokisini. Kukhona into efana ezihambayo ukwephulwa osizayo kokuzalela futhi komama DNA imicu. Ngenxa yalokho, ngokuvamile kwakhiwa kusukela izihibe peptide, okuyinto abakwazi ngokwanele ukuhlanganisa ukulandelana. Ngemva kokususa izingxenye ezingadingekile DNA uchungechunge osizayo izihibe can kokubili resected (ukususa) futhi ihlanganiswe (duplications, okufakiwe). izinguquko achanyuselwa awashintsheki imijikelezo elandelayo cell division.

Ijubane kanye nenombolo yokwanda koshintsho axhomeke isakhiwo eyinhloko-DNA. Abanye ososayensi bakholelwa ukuthi kuba ngokuphelele zonke DNA ye mutagenic uma akha amajika.

Okuvame kakhulu ukuguquka kwezakhi zofuzo nokuguqulwa

Yini uvame ebonakaliswa izinhlayiya eziyisisekelo zofuzo yokwanda koshintsho nokuguqulwa? Izibonelo izimo ezinjalo - ukulahlekelwa elisekela nitrogen nokusula amino acid. Ikakhulukazi sensitive kubo kucatshangwa cytosine izinsalela.

It is wafakazela ukuthi namuhla ezingaphezu kwesigamu ezilwaneni ezinomgogodla ezinamehlo has a ngokuguqula izakhi cytosine izinsalela. Ngemva deamination methylcytosine ishintshelwa-thymine. Izifundo zokulandelisa sigaba iphindwa nephutha noma okususiwe noma kabili futhi iyaguquguquka ukuze isinqamu entsha.

Enye imbangela njalo ukuguquka kwezakhi zofuzo nokuguqulwa kubhekwa inqwaba pseudogenes. Ngenxa yalokhu, ngo-inqubo meiosis zingase zimiswe ukungalingani recombination homologous. Lokhu kuphumela ushintsho izakhi zofuzo ematfuba ngabanye kanye ukubuyelela kabili nucleotide ukulandelana.

imodeli Polymerase mutagenesis

Ngokulandela le-model, ukuguqulwa kwezakhi zofuzo nokuguqulwa zibangelwa okungahleliwe amaphutha amangqamuzana, Kuhlanganisa DNA. Ngokokuqala ngqá kule modeli seyenziwe nge Bresler. Wasikisela ukuthi ukuguquka kwezakhi zofuzo zenzeka ngenxa yokuthi kwezinye izimo, polymerase ufakwa ukulandelana nucleotide nekomplimentarnye.

Eminyakeni ethile kamuva, ngemva ukuhlolwa ezinde ucwaningo, lo mbono sivunyiwe futhi wamukela emhlabeni yesayensi. Ayemaningi ngisho asuswe imithetho ethile ukuthi izovumela ososayensi ukuba ukulawula futhi ukuguquka kwezakhi zofuzo oqondile ukwenekwa ultraviolet izingxenye ezithile DNA. Ngakho, ngokwesibonelo, wathola ukuthi phambi triplet obonakele ngokuvamile eyakhelwe i-adenine.

Tautomeric imodeli mutagenesis

Omunye umbono echaza kuguquka okuvele yokufakelwa kwahlongozwa ngu Watson Crick (ukuthi bangabavumbululi isakhiwo DNA). Basikisela ukuba mutagenesis esekelwe ikhono abanye base-DNA iguqulwe kumafomu tautomeric, ukushintsha elisekela uxhumano indlela.

Ukulandela ukushicilelwa umbono iye ayenziwa. letisha nucleotide zitholiwe ngemva ngemisebe nge ultraviolet. Lokhu kwanika ososayensi entsha yocwaningo amathuba. Isayensi yanamuhla namanje sidingida indima amafomu tautomeric e mutagenesis nokuguqulwa kanye nomthelela wakhona inamba yezinguquko itholiwe.

kweminye imihlobo

kuguquka okuzenzekelayo kungaba ephula ukuqashelwa DNA polymerase acid nucleic. Poltaevym et al yacaciswa indlela ukuthi isebenzisa owayo complementarity simiso synthesis molecule e-DNA ezingaphansi. Le modeli wasivumela ukufunda amaphethini Ukuvela mutagenesis nokuguqulwa. Abacwaningi wachaza ukutholakala kwawo ukuthi isizathu esiyinhloko ekushintsheni isakhiwo DNA zamagama is a non engamukelwa base ngazimbili.

Basikisela ukuba sizathu ukudedela kwenzeka ngenxa deamination ze-DNA. Lokhu kuholela ushintsho cytosine ukuze thymine noma uracil. Ngenxa yalezi ukuguquka kwezakhi zofuzo akhiwa yebhangqa nucleotide engahambelani. Ngakho-ke, ngesikhathi ukufanisana olandelayo kwenzeka izinguquko (esikhundleni ichashaza nucleobases).

Ukwahlukanisa ukuguquka kwezakhi zofuzo: nokuguqulwa

Kunezinhlobo ezahlukene yokwanda koshintsho kuye onjani umbandela okusezinhliziyweni core yabo. Kukhona division of umlingisi lushintsha isakhi sofuzo umsebenzi:

- hypomorphic (soguquko lwegciwane singalawuleka alleles synthesize amaprotheni kancane, kodwa zifana original);
- amorphous (isakhi sofuzo baphelelwa umsebenzi walo);
- antimorfnye (isakhi sofuzo soguquko lwegciwane singalawuleka kushintsha uphawu okuyinto);
- neomorfnye (zikhona izici ezintsha).

Kodwa ngezigaba kwande lapho sihlukanisa zonke ukuguquka kwezakhi zofuzo ngokulingana isakhiwo onhlobonhlobo. avelele:

1. ukuguquka kwezakhi zofuzo ocwaningweni. Lezi zihlanganisa polyploidy, ie kumiswa ufuzo nge kathathu futhi iqoqo Ama-chromosomes e, futhi aneuploidy - inani lezakhi zofuzo e ufuzo akuyona eziningi haploid.
2. Chromosomal wezakhi. Kukhona endabeni yokuhlela kabusha abalulekile izingcezu chromosome. Hlukanisa ukulahleka kolwazi (ukususa), kabili yayo (ukuphindwa), ushintsho orientation ukulandelanisa nucleotide (kombhala), kanye ukudluliswa amasayithi ku-chromosomes enye indawo (translocation).
3. kwezakhi. I ukuguquka kwezakhi zofuzo ezivamile. I chain DNA esikhundleni elisekela eziningana okungahleliwe nitrogen.

Imiphumela yokwanda koshintsho

ukuguqulwa kwezakhi zofuzo okuzenzekelayo - kubangela izifo izimila isitoreji, ukungasebenzi lezitho nezicubu nezilwane. Uma iseli soguquko lwegciwane singalawuleka itholakala ephilayo enkulu ezinamangqamuzana amaningi, kungenzeka kulapho uyobhujiswa kwethulwa apoptosis (yokufa kwamangqamuzana engokwemvelo). Umzimba elawula inqubo ukulondolozwa nesidoda okunikelwe, futhi ngosizo izivikeli mzimba eyoqeda khona bonke amaseli kungenzeka lilimele.

Kwesinye isenzakalo zamakhulu ezinkulungwane T-lymphocyte awunaso isikhathi ukuhlonza isakhiwo abathintekayo, futhi linikeza Clone amaseli aqukethe isakhi sofuzo soguquko lwegciwane singalawuleka. iseli nhlanganisela kakade eminye imisebenzi, uveza ezinobuthi futhi zibulale isimo jikelele zomzimba.

Uma ukuguquka iphutha kuseli ukuphathwa kwabathintwayo futhi lwegciwane, izinguquko sizoba inzalo. Babonisa kwezinso azalwa naso kwezitho, sengozini, iziyaluyalu umzimba, kanye nezifo USB.

ukuguqulwa kwezakhi zofuzo okuzenzekelayo: Inani

Kwezinye izimo, kwabonakala ngaphambilini ukuguquka kwezakhi zofuzo engenamsebenzi angase abe wusizo ukuzivumelanisa nezimo ezintsha zokuphila. Lokhu kuyisimo kuguquka njengoba isilinganiso kwemvelo. Izilwane, izinyoni nezinambuzane babe sifihle coloration elihambisana endaweni yokuhlala ukuze bazivikele ezilwaneni ezidla ezinye izilwane. Kodwa uma ushintsha endaweni yazo, bese usebenzisa i-kuguquka imvelo uzama zokuvikela lezi zilwane yokuqothulwa. Ngaphansi kwale mibandela entsha ezinamandla ukusinda futhi udlulise lo ikhono abanye.

I kuguquka kungaba zenzeka ezindaweni ze-non-asebenzayo zofuzo, bese ubone izinguquko phenotype uyalandelwa. Thola "zokugwema ukuphuka elingapheli" kungenzeka kuphela esebenzisa izifundo ezithile. Kuyadingeka ukufunda umsuka zinhlobo ahlobene kwezilwane kanye ukulungiswa amabalazwe izakhi zabo zofuzo.

Inkinga yokwanda koshintsho nokuguqulwa

Esikhathini forties kwekhulu elidlule kwakukhona umbono ukuthi kuguquka okubangelwa kuphela izici zangaphandle kanye ukubasiza ukuzivumelanisa. Ukuze ukuhlole lokhu ithiyori, ukuhlolwa kanye rep indlela ekhethekile yasungulwa.

Le nqubo yokuthi inombolo encane eyodwa uhlobo bacterium angu kuhlinzwa phezu tube nangemva ukuxhumelela imithi elwa namagciwane amaningi engezwe ke. Ingxenye nezilwanyana ezincane asinda, futhi bayiswa imvelo entsha. Ukuqhathanisa ezahlukene amagciwane amashubhu wembula ukuthi kwaphakama ukumelana angesabi njengoba ukuxhumana ngemithi elwa namagciwane, futhi ngemva kwaso.

ukuphindaphinda indlela kwaba ukuthi indwangu fleecy idluliselwe izilokazane ezincane, bese zidluliselwa kanyekanye ku ezindaweni eziningana ahlanzekile. amakoloni Elisha babengamaJuda cultured futhi ziphathwe elwa namagciwane. Ngenxa yalokho, ama-bacterium ahlukahlukene ngasinda amashubhu ahlelwe ngesikhathi izingxenye alinganayo medium.