El umjikelezo weselula kanye nama-chromosome ayizici ezimbili eziyisisekelo ekuphindaphindeni nasekudluliseleni kolwazi lwezakhi zofuzo ezintweni eziphilayo. Ucwaningo lwalezi zinqubo seluphenduke indawo ebaluleke kakhulu kubhayoloji, okusivumela ukuthi siqonde izindlela ezilawula ukukhula nokuthuthukiswa kwamaseli Kulesi sihloko, sizohlola ngendlela yobuchwepheshe nengathathi hlangothi imiqondo esemqoka yomjikelezo wamaseli nama-chromosome, kanye nokusebenzisana kwawo kanye nokuhambisana kubhayoloji yamaseli.
Isingeniso Se-Cellular Cycle
Umjikelezo weseli Kuyinqubo eyisisekelo yokuzala nokukhula kwamangqamuzana ezinto eziphilayo. Kuwuchungechunge lwezigaba ezihlelekile nezilawulwayo ezivumela amaseli ukuthi ahlukanise ngendlela efanele nangempumelelo.
Kunezigaba ezine eziyinhloko zomjikelezo wamaseli: isigaba se-G1, isigaba S, isigaba se-G2 kanye nesigaba esingu-M. Phakathi nesigaba se-G1, amaseli ayakhula futhi andise umsebenzi we-metabolic. Isigaba sika-S sibalulekile, njengoba kungalesi sikhathi lapho i-DNA yengqamuzana iphindwaphindwa khona, kuqinisekiswe ukuthi ingqamuzana ngalinye lendodakazi linekhophi ephelele yezakhi zofuzo. Kamuva, phakathi nesigaba se-G2, esinye isigaba sokukhula kwamangqamuzana nokulungiselela ukuhlukana kwenzeka. Ekugcineni, isigaba esingu-M, esaziwa nangokuthi i-mitosis, yilapho iseli lihlukana khona bese kukhiqizwa amaseli amantombazane amabili afanayo.
Ukulawulwa okulungile komjikelezo weseli kubalulekile impilo kanye nokusebenza ngendlela efanele kwezinto eziphilayo. Izinguquko ku Le nqubo Zingaholela ezifweni ezinjengomdlavuza, lapho amangqamuzana ekhula futhi ehlukana ngokungalawuleki. Ngakho-ke, kubaluleke kakhulu ukuqonda kahle umjikelezo weseli kanye nezindlela zokulawula eziwulawulayo. Lezi zindlela zihlanganisa amaprotheni abizwa ngokuthi ama-cyclins kanye nama-cyclin-dependent kinases, asebenza njengezilawuli ezibalulekile ezigabeni ezihlukene zomjikelezo weseli.
Ngamafuphi, umjikelezo umakhalekhukhwini kuyinqubo kubalulekile ekuthuthukisweni nasekusebenzeni kahle kwezinto eziphilayo Ngezigaba zazo ezihlukene, amaseli ayahlukana futhi azalane, okuqinisekisa ukukhula nokuvuselelwa kwezicubu nezitho. Ukulawula kwayo okulungile kuyisihluthulelo ekuvimbeleni izifo nokugcina i-homeostasis yeselula. Ngokutadisha nokuqonda umjikelezo wamaseli, singathola umbono ophelele kakhudlwana webhayoloji yamangqamuzana nezinqubo ezibalulekile ezenzeka emizimbeni yethu.
Incazelo Nezigaba Zomjikelezo Weseli
Izigaba Zomjikelezo Weseli
Umjikelezo wamaseli kuyinqubo wonke amaseli adlula kuyo impilo yawo yonke. Lo mjikelezo uhlukaniswe izigaba eziningana, ngasinye sinomsebenzi othile kanye nezici eziyingqayizivele eziqinisekisa ukukhula nokuthuthuka kwamangqamuzana okulungile. Izigaba ezintathu eziyinhloko zomjikelezo weseli zichazwe ngezansi:
- Isigaba G1 (Igebe 1): Kulesi sigaba, ingqamuzana lilungiselela ukuphindaphinda i-DNA yalo. Ngalesi sikhathi, iseli lihlanganisa amaprotheni futhi likhule ngosayizi, ukuze kuqinisekiswe ukuthi linezinsiza ezanele zokuhlukaniswa kwamaseli okulandelayo.
- Isigaba S (Ukuhlanganiswa): Phakathi nalesi sigaba, ingqamuzana liphindaphinda i-DNA yalo. Ngamunye wemicu ye-DNA ikopishwa ukuze yakhe imicu emibili efanayo, kamuva ezosatshalaliswa kumaseli endodakazi.
- Isigaba G2 (Igebe 2): Kulesi sigaba, iseli lilungiselela ukuhlukaniswa kwamaseli. Ngalesi sikhathi, iseli liyaqhubeka nokuhlanganisa amaprotheni futhi likhule ngosayizi, njengaseSigabeni se-G1. Ukuqinisekiswa nokulungiswa kwe-DNA nakho kwenziwa ngaphambi kokuhlukaniswa.
Lezi zigaba ze cell umjikelezo kukhona kubalulekile ekukhuleni nasekugcinweni kwezicubu ezinhlobonhlobo zamangqamuzana amaningi. Isigaba ngasinye senziwa ngendlela enembile futhi ehlelekile, ehlanganiswe uchungechunge lwezimpawu kanye nezindlela zokulawula eziqinisekisa ubuqotho bezakhi zofuzo nokuqhubeka okulungile komjikelezo. Umjikelezo wamaseli uyinqubo eqhubekayo, kodwa ngaphansi kwezimo ezithile, amaseli angangena esigabeni esibizwa ngokuthi i-G0, lapho ehlala ethule futhi engahlukani.
Ukubaluleka Kokuphindaphinda Kwe-DNA Kumjikelezo Weseli
Ukuphindaphinda kwe-DNA kuyinqubo ebalulekile emjikelezweni weseli okuqinisekisa ukudluliswa okunembile kolwazi lofuzo lusuka kungqamuzana lomama luye kumaseli endodakazi yalo. Ukubaluleka kwayo kusezicini eziningana ezibalulekile:
1. Ukulondolozwa kolwazi lofuzo: Ukuphindaphinda kwe-DNA kuvumela ingqamuzana ngalinye lendodakazi ukuthi lithole ikhophi efanayo yezakhi zofuzo zeseli lomzali. Lokhu kuqinisekisa ukuthi izici nemisebenzi ezuzwe njengefa kugcinwa kusukela kwesinye isizukulwane kuya kwesinye, ngaleyo ndlela kugcina ubuqotho bezinto eziphilayo.
2. Ukulungisa Nokulungiswa Kweziphazamisi: Ngesikhathi sokuphindaphinda kwe-DNA, indlela yokuhlola nokulungisa ama-enzyme idlala indima ebalulekile ekutholeni nasekulungiseni amaphutha okungenzeka noma umonakalo ochungechungeni lwe-DNA. Lokhu kulungiswa kuvimbela ukuqoqwa kokuguqulwa kofuzo futhi kuqinisekise ukuzinza kwe-genomic yesikhathi eside.
3. Ukukhiqizwa kwamaprotheni kanye nokulawulwa kwamaselula: Ukuphindaphinda kwe-DNA kunikeza isisekelo sokwakheka kwamaprotheni, njengoba ulwazi lofuzo olugcinwe ku-DNA lubhalwa futhi luhunyushwe kusithunywa i-RNA (mRNA). I-mRNA, yona, isebenza njengesifanekiso se-protein synthesis, edlala indima ebalulekile ekusebenzeni nasekulawuleni izinqubo zamaselula.
Izindlela Zokulawula Ze-Cellular Cycle
Zibalulekile ukugcina ubuqotho kanye nokulingana kwamaseli. Lezi zindlela ziqinisekisa ukuthi amaseli ahlukana ngendlela efanele nokuthi izinto zofuzo zisatshalaliswa ngendlela efanele phakathi kwamaseli amadodakazi. Ngochungechunge lwezehlakalo eziqondisiwe nezilawulwayo, inqubekelaphambili yomjikelezo weseli iyagadwa futhi izimpendulo zokulungisa amaphutha zenziwe zisebenze uma kudingeka.
Kunezindlela ezimbalwa ezibalulekile eziqinisekisa ukulawulwa okulungile komjikelezo weseli. Enye yazo iyindawo yokuhlola esigabeni se-G1, lapho kuhlolwa khona ukuthi iseli selikulungele yini ukuqala ukuphindaphinda kwalo noma uma lidinga isikhathi esengeziwe ukuze likhule futhi lithuthuke ngendlela efanele. Enye indlela ebalulekile indawo yokuhlola esigabeni se-G2, eqinisekisa ukuthi umonakalo we-DNA ulungisiwe yini ngaphambi kokungena esigabeni sokuhlukaniswa kwamaseli.
Ukwengeza, umjikelezo weseli ulawulwa yizinto ezilawulayo ezibizwa nge-cyclin-dependent kinases (CDKs) nama-cyclins. Lawa maprotheni enza ama-complexes asebenza ngokuhlukile izigaba zomjikelezo wamaseli. Isibonelo, i-CDK4/cyclin D inesibopho sokuqalisa umjikelezo weseli esigabeni se-G1, kuyilapho i-CDK1/cyclin B ilawula ukungena esigabeni esingu-M, lapho kwenzeka khona ukuhlukaniswa kwamaseli nokwenziwa kusebenze kwalawa ma-kinase, kanye nezinye izindlela zokulawula. qinisekisa ukuthi umjikelezo wamaseli uqhubeka kahle nokuthi amaphutha angaholela ekwandeni kwamaseli okungalawuleki ayagwenywa.
Iqhaza Le-Chromosome Kumjikelezo Weseli
Umjikelezo wamaseli uyinqubo eyisisekelo yokuphila kwawo wonke amangqamuzana asemzimbeni wethu. Phakathi nalo mjikelezo, amaseli ahlukanisa futhi akhiqize ngendlela elawulwayo, okuvumela ukukhula nokuvuselelwa kwezicubu nezitho ze-Chromosome, ezakhiwe i-DNA namaprotheni, adlala indima ebalulekile kule nqubo, iqinisekisa ukuhlukaniswa okulungile kwezakhi zofuzo kanye nokufika. yekhophi ephelele yolwazi esitokisini sendodakazi ngayinye.
Esinye sezehlakalo ezivelele kakhulu kumjikelezo weseli ukuphindaphinda kwama-chromosome Phakathi nesigaba sika-S, i-DNA equkethwe kuma-chromosome iphindwaphindwa ukuze yakhe amakhophi amabili afanayo. Lawa makhophi, aziwa ngokuthi ama-chromatids angodade, ahlala ehlangene endaweni ebizwa ngokuthi i-centromere aze ahlukane phakathi nesigaba esingu-M Ukusabalalisa okulungile kwama-chromatid amantombazane kumaseli endodakazi kubalulekile ukuze kugcinwe ukuzinza kofuzo nokuvimbela ukuphuma kwe-chromosomal.
Ngokungeziwe endimeni yawo ekuphindaphindeni nasekuhlukaniseni i-DNA, ama-chromosome aphinde adlale indima ebalulekile ekulawuleni umjikelezo weseli Ukwakheka kwama-chromosome nokuhlelwa kwawo ku-nucleus yeseli kunikeza isikafula esibonakalayo esivumela ukwenziwa okufanele kwezinyathelo zomjikelezo. Amaprotheni athile abophezela kuma-chromosome ngezikhathi eziqondile ukuze enze kusebenze noma avimbele ukuqhubeka komjikelezo, okuqinisekisa ukusebenzisana okwanele phakathi kwezigaba ezihlukene. Lezi zindlela zokulawula zibalulekile ekuvimbeleni ukwanda kwamangqamuzana okungalawuleki, okungaholela ekwakhekeni kwezifo ezinjengomdlavuza.
Inhlangano kanye Nesakhiwo Se-Chromosome
Ama-Chromosome ayizakhiwo ezihleleke kakhulu futhi abalulekile ekusebenzeni kahle kwamaseli. Ingqamuzana ngalinye linenani elithile lama-chromosome, elihluka kuye ngohlobo lwezinhlobo. Kubantu, ngokwesibonelo, kunamapheya angama-23 ama-chromosome, enani lama-chromosome angama-46.
Isakhiwo esiyisisekelo se-chromosome sakhiwe izingalo ezimbili, emfishane eyaziwa ngokuthi "p" kanye nende eyaziwa ngokuthi "q". Ngokulandelayo, ingalo ngayinye ihlukaniswe yaba izifunda ezithile ezibizwa ngokuthi amabhande ama-chromosome. Lawa mabhande abonakala ngaphansi kwesibonakhulu esikhethekile ngesikhathi senqubo yokufaka amabala.
Ngokungeziwe ekwakhekeni kwawo okungokomzimba, ama-chromosome aphinde abe nokuhleleka ezingeni lofuzo I-chromosome ngayinye iqukethe izakhi zofuzo, ezilandelanayo ze-DNA ezinomthwalo wemfanelo wokufaka amakhodi amaprotheni nokulawula imisebenzi ehlukahlukene yamaselula. Lezi zakhi zofuzo zihlelwe zaba izingxenye ezibizwa ngokuthi i-loci, ezihlelwe ngendlela ethile kuyi-chromosome.
I-Cell Cycle and Cell Division
Umjikelezo weseli yinqubo iseli elidlula kuyo ukuze likhule futhi lihlukane libe amaseli amantombazane amabili. Le nqubo iqukethe izigaba ezihlukene futhi iqinisekisa ukuphindaphinda nokusatshalaliswa kwento yofuzo. Ukuhlukaniswa kwamaseli, ngakolunye uhlangothi, kuyinqubo lapho ingqamuzana likamama lihlukana libe amangqamuzana amantombazane amabili asebenza ngokugcwele.
Umjikelezo wamaseli uhlukaniswe izigaba ezine eziyinhloko: isigaba se-G1 (igebe 1), isigaba S (ukuhlanganiswa), isigaba se-G2 (igebe lesi-2) kanye nesigaba esingu-M (mitosis). Phakathi nesigaba se-G1, iseli liyakhula futhi lenze imisebenzi evamile ye-metabolic, lilungiselela ukuhlukaniswa kwamaseli. Esigabeni sika-S, ukuphindaphinda kwe-DNA kwenzeka, lapho ikhromozomu ngayinye iphindwaphindwa ukuze yakhe amakhophi amabili afanayo. Khona-ke, esigabeni se-G2, iseli liyaqhubeka nokukhula futhi lilungiselela isigaba esilandelayo.
Ekugcineni, sifinyelela esigabeni esingu-M, okuyisigaba sokuhlukaniswa kwamaseli ngokwaso. Lesi sigaba sihlukaniswe ngezigaba eziningana: i-prophase, i-metaphase, i-anaphase ne-telophase Ngesikhathi se-prophase, ama-chromosome ayancipha futhi i-mitotic spindle iqala ukwakheka. Ku-metaphase, ama-chromosome aqondana maphakathi neseli, kuyilapho ku-anaphase, ama-chromatids angudade ahlukene futhi adonselwa ezigxotsheni eziphambene zeseli. Ekugcineni, phakathi ne-telophase, ama-chromosome ayancipha, akhe ama-nuclei futhi, bese kuba i-cytokinesis, lapho ingqamuzana lihlukana libe kabili.
Ukulawulwa Kwezofuzo Kumjikelezo Weseli
Umjikelezo wamaseli yinqubo elawulwa kakhulu eyenzeka kumaseli e-eukaryotic ukuqinisekisa ukukhula nokuhlukana kwawo. Ukulawulwa kwezakhi zofuzo kudlala indima ebalulekile kulo mshini oyinkimbinkimbi, olawula ngokunembile uguquko ukusuka kwesinye isigaba ukuya kwesinye.
Enye yezindlela eziyinhloko ekulawuleni izakhi zomjikelezo weseli ukuvezwa kwezakhi zofuzo ezithile ngezikhathi ezithile. Phakathi nesigaba se-G1, izakhi zofuzo ezikhuthaza ukukhula kwamangqamuzana kanye nokuphindaphindwa kwezakhi zofuzo ziyasebenza, kuyilapho esigabeni sika-S, izakhi zofuzo ezihlobene nokuphindaphinda kwe-DNA zivezwa kakhulu.
Ngaphezu kokulawulwa kokuvezwa kofuzo, ukulawulwa kwangemuva kokuhumusha nakho kudlala indima ebalulekile kumjikelezo weseli. Amaphrotheni afana ne-cyclin-dependent kinase anesibopho sokwenza kusebenze izici zokuloba kanye nama-enzyme abalulekile abandakanyekayo ekuqhubekeleni phambili komjikelezo weseli. Ngokufanayo, ukuwohloka kwamaprotheni ayisihluthulelo, okulawulwa yi-proteasome complex, kuvumela ukuguqulwa kwesigaba esisodwa kuya kwesinye.
Izinguquko Ze-Chromosomal kanye Nomthelela Wazo Kumjikelezo Weseli
Ukuguqulwa kwe-Chromosomal izinguquko esakhiweni noma enanini lama-chromosome, okungaba nomthelela omkhulu kumjikelezo weseli kanye nezinqubo zebhayoloji eziyisisekelo. Lezi zinguquko zingavela ngenxa yamaphutha ekuphindaphindeni kwe-DNA, ukuhlanganiswa kabusha kofuzo, noma ukuhlukaniswa kwe-chromosome phakathi nokuhlukaniswa kwamaseli. Ngezansi, sizohlola ezinye eziyinhloko.
Olunye loshintsho oluvame kakhulu lwe-chromosome i-aneuploidy, esho izinguquko enanini lama-chromosome kuseli. Lesi simo singaholela ekulahlekelweni noma ekuzuzeni ama-chromosome aphelele noma ingxenye, okushintsha ngokuphawulekayo ibhalansi yofuzo. I-Aneuploidy ingaphazamisa umjikelezo weseli, njengoba umshini wamangqamuzana onesibopho sokuphindaphinda kwe-DNA nokuhlukaniswa kwe-chromosome ingase ingasebenzi kahle kumaseli ane-chromosome ehambisanayo engajwayelekile.
Okunye ukuguqulwa kwe-chromosomal okufanelekile ukudluliselwa kwendawo, okubandakanya ukushintshaniswa kwamasegimenti e-chromosomal phakathi kwama-chromosome angewona ama-homologous. Lokhu kungashintsha ukusho okuvamile kofuzo futhi kuthinte izakhi zofuzo ezibalulekile ezilawula umjikelezo weseli. Ukwengeza, ukuguqulwa kwe-chromosomal, lapho ingxenye ye-chromosome ihlehliswa endaweni yayo, ingashintsha ukupakishwa kwe-DNA kanye nokuxhumana phakathi kwama-chromosome, kuthonye ukuphindaphinda kwe-chromosome nokuhlukaniswa.
Izifo Ezihambisana Ne-Chromosomal Anomalies
Kukhona okuningana okungathinta kakhulu impilo nokuthuthuka komuntu. Lezi zinguquko zofuzo zingenzeka kunoma ubani, kungakhathaliseki ubulili noma ubudala. Ngezansi ezinye zezifo ezivame kakhulu ezihlobene nokungajwayelekile kwe-chromosomal:
I-Down's Syndrome: Eyaziwa nangokuthi i-trisomy 21, lesi sifo sibangelwa ikhophi eyengeziwe ye-chromosome 21. Abantu abane-Down syndrome bavame ukuba nezici zomzimba ezihlukile, ukubambezeleka kokukhula, nokukhubazeka kwengqondo.
I-Turner syndrome: Lesi sifo senzeka kwabesifazane futhi sibonakala ngokungabikho ngokuphelele noma ingxenye ye-X chromosome Abantu abane-Turner syndrome bangase babe nesiqu esifushane, ukukhubazeka kwenhliziyo kanye nezinkinga zezinso, kanye nobunzima ekukhuleni kocansi nokuzala.
I-Klinefelter syndrome: Kulesi sifo, abesilisa bane-X chromosome eyengeziwe, okuholela kusethi ye-XXY chromosome esikhundleni se-XY evamile. Abantu abane-Klinefelter syndrome bangase babe nokuthuthukiswa kwezicubu zebele okungavamile, ukukhiqizwa kwesidoda esincane, nobunzima bokufunda nokukhuluma.
Ukubaluleka Kokulondoloza I-Chromosome Phakathi Nomjikelezo Weseli
Ukulondolozwa kwama-chromosome phakathi nomjikelezo weseli kubaluleke kakhulu ukuze kugcinwe ukuzinza kwe-genomic nokuvimbela ukuguqulwa kwezakhi zofuzo nezifo. Phakathi Kwesigaba sokuphindaphinda kwe-DNA, i-chromosome ngayinye iphinda kabili ngokwethembeka, iqinisekisa ukuthi iseli ngayinye yendodakazi entsha ithola ikhophi ephelele yento yokuqala yofuzo. Lokhu kuqinisekisa ukudluliswa okunembile kolwazi lofuzo ezizukulwaneni ezizayo.
Ngaphezu kwalokho, ukugcinwa okufanele kwama-chromosome kubalulekile ngesikhathi sokuhlukaniswa kwamaseli. Ngesikhathi se-mitosis, ama-chromosome ahlangana futhi aqondanise epuleti le-equatorial, okuvumela ukuhlukaniswa okufanele kwamakhophi e-DNA kumaseli amantombazane. Iphutha ekongiweni kwama-chromosome phakathi nale nqubo lingaholela ekuphambukeni kwe-chromosomal, njenge-aneuploidy, ehlotshaniswa nezifo zofuzo nomdlavuza.
Ukuze kuqinisekiswe ukulondolozwa kwama-chromosome, amaseli asebenzisa izindlela zokulawula ezinembile. Izindawo zokuhlola umjikelezo weseli Bahlala beqapha ubuqotho be-DNA futhi bavimbele ukuqhubekela phambili esigabeni esilandelayo uma kutholwa umonakalo noma amaphutha. Ngesikhathi sokuphindaphinda kwe-DNA, izindlela zokulungisa i-DNA ziqinisekisa ukuthi noma yimuphi umonakalo uyalungiswa ngaphambi kokuba amakhophi e-DNA ahlukane. Ngaphezu kwalokho, amaprotheni abopha i-centromere adlala indima ebalulekile ekuhlukaniseni okulungile kwama-chromosome ngesikhathi se-mitosis.
Intuthuko Kumjikelezo Weseli kanye Nocwaningo Lwe-Chromosome
Ukulawulwa komjikelezo weseli:
Umjikelezo weseli uwuchungechunge lwezehlakalo eziholela ekuphindeni kanye nokuhlukaniswa kweseli. Ukulawulwa okufanele kwale nqubo kubalulekile ukuze kugcinwe ubuqotho nokuzinza komzimba. Eminyakeni yamuva nje, kuye kwenziwa intuthuko ethakazelisayo ekuqondeni izinqubo zamangqamuzana ezihilelekile ekulawuleni umjikelezo wamangqamuzana.
Imishini yamaselula enesibopho sokulawula le nqubo itholwe ukuthi ihlanganisa amaprotheni abalulekile okulawula, afana nama-cyclin-dependent kinases (CDKs) nama-cyclins. Lawa maprotheni akha ama-complexes asebenza njengamaswishi ukuze aqalise ukuqhubeka ngezigaba ezihlukene zomjikelezo weseli. Ngaphezu kwalokho, ukucekelwa phansi kwamaprotheni okukhethiwe, okulamulwa uhlelo lwe-ubiquitin-proteasome, kutholakale ukuthi kunendima ebalulekile ekulawuleni okunembile kwesikhathi nokulandelana kwezenzakalo kumjikelezo weseli.
Ukubaluleka kwama-chromosomes:
Ama-Chromosome ayizakhiwo ezihleleke kakhulu eziqukethe ulwazi lofuzo lwento ephilayo. Ucwaningo lwakamuva luye lwembula imininingwane ethakazelisayo yendlela ama-chromosome ahlelwa futhi ahlukaniswa ngayo phakathi nokuhlukaniswa kwamaseli. Kutholwe ukuthi ama-chromosome ahlelwa ezizindeni zesakhiwo ezibizwa ngokuthi izizinda ezihambisana ne-topologically (TAD) nokuthi le nhlangano idlala indima ebalulekile ekuhlukaniseni ama-chromosome okulungile.
Ngaphezu kwalokho, ngokusebenzisa amasu e-microscopy esezingeni eliphezulu, kube nokwenzeka ukubona ngokuningiliziwe ukuguquguquka kwama-chromosome phakathi nomjikelezo weseli. Lokhu kuthuthuka kusivumele ukuthi siqonde kangcono indlela ama-chromosome ahlanganiswe futhi ancipha ngayo ezigabeni ezihlukene zomjikelezo weseli, kanye nendlela ukuthuthela kwawo okunembayo kuya ezigxotsheni zeseli kuxhumananiswa kanjani phakathi nokuhlukana kwamaseli.
Ukuthuthuka kwezobuchwepheshe ocwaningweni:
Umjikelezo wamaseli nocwaningo lwekhromozomu luzuze kakhulu ekuthuthukisweni kwezobuchwepheshe eminyakeni yamuva. Ukuvela kwamasu okulandelana kwesizukulwane esilandelayo kuye kwavumela ukucwaninga okuphelele kwezinguquko enkulumweni yofuzo ezenzeka kuwo wonke umjikelezo weseli. Lokhu kwembule inethiwekhi eyinkimbinkimbi neguqukayo yokulawulwa kofuzo ehlotshaniswa nezehlakalo ezihlukene zomjikelezo weseli.
Ukwengeza, ukuthuthukiswa kwamasu e-microscopy e-super-resolution kuye kwavumela abacwaningi ukuthi bathole izithombe zokulungiswa okuphezulu kwama-chromosome futhi babheke imininingwane yesakhiwo engakaze ibonwe ngaphambili. Lawa masu abe nesandla ekuchazeni ukwakheka kwe-3D yamakhromozomu nokuqonda kangcono ukuthi ahlelwa futhi ahlukaniswa kanjani phakathi nokuhlukaniswa kweseli.
Izicelo Zokwelapha Ezingenzeka Ezivela Ocwaningweni Lomjikelezo Weseli kanye nama-Chromosomes
Ucwaningo lomjikelezo weseli nama-chromosome luvula umnyango wezinhlelo eziningi zokwelapha emkhakheni wezokwelapha. Okulandelayo, sizokwethula ezinye zezicelo ezingase zivele kulolu cwaningo:
1. Ukuxilongwa nokwelashwa kwezifo zofuzo: Ukuqonda okuphelele komjikelezo weseli namakhromozomu kubalulekile ukuze kukhonjwe futhi kuhlonzwe izifo zofuzo. Ngokutadisha izinguquko ekwakhekeni nasekusebenzeni kwama-chromosome, abacwaningi bangakwazi ukunquma imbangela yofuzo ewumsuka yezifo ezinjenge-Down syndrome, i-hemophilia, nomdlavuza. Lokhu kuvumela ukuxilonga okunembile futhi, ngokulandelayo, ukwelashwa okuphumelelayo, noma ngabe ngokwelashwa kofuzo noma ukungenelela okuthile kwemithi.
2. Ukwelashwa kwamaselula nokuvuselela kabusha: Ulwazi lomjikelezo wamaseli lubalulekile ekuthuthukisweni kwezindlela zokwelapha zamaselula nezivuselelayo. Abacwaningi bangasebenzisa lolu lwazi ukuze balawule umjikelezo weseli futhi bakhuthaze ukuvuselelwa kwezicubu ezilimele noma ezigulayo. Isibonelo, endabeni yokulimala komgogodla, intuthuko ethembisayo yenziwe ngokuxhaphaza umjikelezo weseli lama-stem cells ukuze kukhuthazwe ukulungiswa kwezicubu ezithintekile.
3. Ukuthuthukiswa kwemithi ethile: Ucwaningo lomjikelezo weseli nama-chromosome lungaholela ekutholweni nasekuthuthukisweni kwemithi ethile yokwelapha izifo ezihlobene. Ukuqonda ukuthi ama-chromosome asebenza kanjani nokuthi alawulwa kanjani kumjikelezo weseli kunikeza ithuba lokuhlonza okungaba okuqondiwe kwezidakamizwa. Lokhu kungaholela emithini esebenza ngempumelelo futhi ekhethiwe, kuncishiswe imiphumela engemihle futhi kuthuthukiswe izinga lempilo yeziguli.
Q&A
Q: Uyini umjikelezo weseli?
IMP: Umjikelezo weseli yinqubo amaseli adlula ngayo kusukela ekwakhekeni kwawo kuya ekuhlukaneni kwawo abe amaseli amantombazane amabili. Le nqubo ihlanganisa izigaba ezahlukene ezibizwa ngezigaba zomjikelezo weseli.
Q: Yiziphi izigaba zomjikelezo weseli?
A: Izigaba zomjikelezo weseli yilezi: G1 (isigaba sokukhula 1), S (isigaba sokuhlanganisa), G2 (isigaba sokukhula 2) kanye noM (isigaba se-mitosis). Phakathi nalezi zigaba, iseli lilungiselela ukuphindwaphindwa kofuzo lwalo kanye nokuhlukaniswa okulandelayo.
Q: Kwenzekani phakathi nesigaba se-G1 somjikelezo weseli?
A: Phakathi nesigaba G1, iseli lizwa ukukhula nomsebenzi oqinile we-metabolic. Kulesi sigaba, izingxenye ezidingekayo zokuphindaphinda kwe-DNA ziyahlanganiswa futhi iseli lilungiselelwa isigaba esilandelayo.
Q: Futhi esigabeni S somjikelezo weseli?
A: Ngesikhathi sesigaba sika-S, iseli lenziwa i-DNA synthesis noma ukuphindaphinda. Lokhu kusho ukuthi i-chromosome ngayinye iphinda izinto zayo zofuzo, yakhe izakhiwo ezibizwa ngokuthi ama-chromatids angudade. Ekupheleni kwalesi sigaba, ingqamuzana lizoba ne-DNA ephindwe kabili kunangaphambi kokuqala kwesigaba sika-S.
Q: Kwenzekani phakathi nesigaba se-G2?
A: Phakathi nesigaba se-G2, iseli liyaqhubeka nokukhula futhi lilungiselela ukuhlukaniswa kwamaseli. Kulesi sigaba, ukuhlanganiswa kwamaprotheni adingekayo ukuze kuhlukaniswe amaseli kwenzeka futhi kuyaqinisekiswa ukuthi i-DNA iphindwe ngendlela efanele.
Q: Isiphi isigaba sokugcina somjikelezo weseli?
A: Isigaba sokugcina somjikelezo weseli yisigaba esingu-M, esaziwa nangokuthi yisigaba se-mitosis. Kulesi sigaba, ukuhlukana kwe-nucleus nama-chromosome kwenzeka, okukhiqiza amangqamuzana amantombazane amabili afana elinye nelinye neseli likamama.
Q: Ayini ama-chromosome?
A: Ama-Chromosome yizakhiwo ezakhiwe nge-DNA namaprotheni, akhona ku-nucleus yeseli. Ziqukethe izakhi zofuzo futhi zinomthwalo wemfanelo wokudlulisa ulwazi lofuzo lusuka kwesinye isizukulwane luye kwesinye.
Q: Mangaki ama-chromosome akhona kungqamuzana lomuntu?
A: Emangqamuzaneni omuntu, kunama-chromosome angu-46, ahlelwe aba ngamapheya angu-23. Ipheya ngalinye liqukethe i-chromosome eyodwa evela kubaba nenye evela kumama.
Q: Kwenzekani ngesikhathi se-mitosis maqondana nama-chromosome?
A: Ngesikhathi se-mitosis, ama-chromosome ayajiya ukuze enze kube lula ukuhlukana kwawo futhi asatshalaliswa ngokulinganayo phakathi kwamaseli endodakazi. Ingqamuzana ngalinye lendodakazi lithola ikhophi ye-chromosome ngayinye ekhona kuseli lomzali.
Q: Kwenzekani uma izinguquko zenzeka kumjikelezo weseli noma kuma-chromosome?
IMP: Izinguquko kumjikelezo weseli noma kuma-chromosome kungaholela ezifweni zofuzo, ukuguqulwa kwezakhi zofuzo noma i-carcinoma. Lezi zinguquko zingabangelwa izici ezihlukahlukene, njengemisebe, amakhemikhali, noma amaphutha ngesikhathi sokuphindaphinda kwe-DNA.
Amazwana okugcina
Sengiphetha, umjikelezo weseli nama-chromosome kuyizici ezibalulekile ekuphindaphindeni kanye nefa lezinto zofuzo eziphilayo. Kuso sonke lesi sihloko, sihlole izehlakalo ezehlukene ezenzeka phakathi nomjikelezo wamaseli, ukusuka esigabeni se-interphase ukuya ekuhlukaniseni kwamaseli i-mitosis kanye ne-meiosis. Siphinde sahlola ukwakheka nokusebenza kwama-chromosome, sigqamisa ukubaluleka kwawo ekuhlelweni nasekudlulisweni kolwazi lofuzo.
Kubalulekile ukuqaphela ukuthi umjikelezo weseli nama-chromosome kuyizihloko eziyinkimbinkimbi futhi eziguqukayo, ezingaphansi kocwaningo olubanzi nokutholwa okuqhubekayo emkhakheni wesayensi. Njengoba siqhubekisela phambili ulwazi lwethu, kuphakama imibuzo emisha nezinselele ezisishukumisela ukuthi siqhubeke nokucwaninga nokujulisa ukuqonda kwethu lezi zinqubo.
Ukuqonda umjikelezo weseli nama-chromosome kunemithelela ebalulekile kukho kokubili impilo yomuntu nobunjiniyela bofuzo. Ulwazi lwalezi zinqubo lungaba nomthelela ekuxilongweni nasekwelapheni izifo ezihlobene nokuguqulwa kwe-chromosomal, kanye nokukhohlisa kofuzo ngezinjongo zokwelapha noma zokuthuthukisa izitshalo.
Ngamafuphi, ukucwaninga komjikelezo weseli nama-chromosome kubalulekile ukuze kuqondwe isisekelo sofuzo lokuphila kanye nokusebenza kwezinto eziphilayo. Njengoba sijulisa ukuqonda kwethu lezi zinqubo, sivula amathuluzi abalulekile ukuze sibhekane nezinselele zesayensi nezokwelapha, futhi siqhubeke nokufuna izimpendulo zendida yemfuzo nokuziphendukela kwemvelo.
Ngingu-Sebastián Vidal, unjiniyela wekhompyutha ozifelayo ngobuchwepheshe kanye ne-DIY. Ngaphezu kwalokho, ngingumdali we tecnobits.com, lapho ngabelana khona ngezifundo zokwenza ubuchwepheshe bufinyeleleke kakhudlwana futhi buqonde wonke umuntu.