Gene, ufuzo, chromosome: definition, ukwakheka kwazo, imisebenzi

"Gene", "zofuzo,", "chromosome" - amagama ajwayelekile zonke wesikole. Kodwa umqondo wokuthi lolu daba sasivumela generalized sijulise ehlathini kwamakhemikhali kudinga ulwazi olukhethekile kanye isifiso ukuqonda konke. Futhi, uma ikhona ezingeni ilukuluku, iphele masinyane ngaphansi isisindo isethulo. Ake sizame ukuqonda butholakala enqubweni eyinkimbinkimbi yokuthela ukwaziswa kwezakhi zofuzo efomini yezesayensi nasezinzuzweni polar.

Kuyini isakhi?

Gene - the kuyizinhlayiyana kulencane kolwazi kwesakhiwo obusebenzayo ufuzo eziphilayo. Empeleni obuncane DNA, equkethe ulwazi mayelana ethize acid acid ukulandelana ukwakha amaprotheni noma RNA obusebenzayo (okuzokwenziwa wabuye kwemiqondo amaprotheni). Isakhi inquma izici ukuthi zizuzwe wadlula kodwa uhlangulisa inzalo ka iketango ngokwezinhlu zozalo. Ezinye eziphilayo owumphumela, kukhona ukudluliswa isakhi sofuzo, okuyinto angahambisani kabusha uhlobo yabo, ibizwa ngokuthi ovundlile.

"Ngo emahlombe" zezakhi zofuzo kungumsebenzi omkhulu ngoba uyobheka kanjani futhi sisebenze wonke amangqamuzana nomzimba iyonke. Ilawula ezimpilweni zethu kusukela ngomzuzu wokukhulelwa kuwo umoya wokugcina.

Isinyathelo sokuqala yesayensi phambili ekutadisheni ufuzo esenziwa monk Austrian Gregor Mendel, ngubani ngo-1866 eshicilelwe imibono yakhe phezu imiphumela Ukunqamula uphizi. impahla Ukubambezeleka, awusebenzisa ngokucacile izibonakaliso lwamaphethini ukudluliswa, ezifana umbala kanye ukuma uphizi izimbali. Lokhu indela washayelwa imithetho Owadala ekuqaleni zofuzo njengendlela isayensi. Ifa zezakhi zofuzo Ngenxa yokuthi abazali benika izingane zabo ngoba uhhafu wama-chromosomes yayo. Ngakho, izimpawu umama nobaba, ukuxuba ukwakha inhlanganisela entsha izici ezikhona kakade. Ngenhlanhla, izinketho ziningi kunezinwele eziphilayo emhlabeni, futhi kuyinto engenakwenzeka ukuba uthole izidalwa ezimbili ngokuphelele ezifanayo.

Mendel wabonisa ukuthi yokuba izici zofuzo eziyingozi akuzona exubile, futhi kuthiwa ngocansi ngesimo leyehlukene (ehlukile) amayunithi kubazali enzalweni. Lezi amayunithi ziboniswa zezinhlobo ngazimbili (alleles) ukuhlala ngokuqhubekayo futhi adluliselwa lempumelelo izizukulwane e gametes iduna nensikazi, ngamunye equkethe eyodwa iyunithi pair ngamunye. Ngo-1909, isazi sezitshalo Danish Johannsen ngokuthi lezi amayunithi lokhu ngezakhi ezingamaqoqo. Ngo-1912, isazi sezakhi zofuzo sase-United States of America, Morgan yabonisa ukuthi zingabantu kuma-chromosome.

Kusukela ngaleso sikhathi, kwathatha engaphezu kweyikhulu nesigamu, futhi izifundo isihambile nakude kunamazwi Mendel ngikucabange. Okwamanje, ososayensi baye kuxazululwe phezu umbono ukuthi yikuphi ukwaziswa okugcinwe kwi izakhi zofuzo, inquma wekukhula, intfutfuko kanye umsebenzi yezinto eziphilayo. Futhi mhlawumbe kwaba sekufeni kwabo.

ngezigaba

kwezakhi zofuzo iqukethe Ukwaziswa hhayi kuphela mayelana amaprotheni, kodwa futhi abonisa ukuthi ufunde nini futhi kanjani, futhi iziza ezingenalutho ezidingekayo ukuze wabelane ngolwazi mayelana amaprotheni ezahlukene kanye ukumisa zamagama zishintshe ulwazi.

Kukhona izinhlobo ezimbili zezakhi zofuzo:

1. Wezakhiwo - aqukethe ulwazi mayelana nesakhiwo amaprotheni noma RNA ngamaketanga. Ukulandelana nucleotide sifana amino acid.
2. zezakhi zofuzo Functional obhekene isakhiwo efanele asele DNA izingxenye ukulandelana synchronism, nokulifunda.

Kuze kube manje, ososayensi bayakwazi uphendula lo mbuzo: bangaki zofuzo-chromosome? Impendulo kuyokushiya umangele: ezingaba yizigidi eziyizinkulungwane ezintathu ngazimbili. Futhi lena ingenye amabili nantathu kuphela. Genome luncane iyunithi kwesakhiwo, kodwa ungashintsha umuntfu lakhetsa kuphila ngato.

ukuguqulwa kwezakhi zofuzo

ushintsho ngephutha noma ngamabomu nucleotide ukulandelanisa ngaphakathi Strand DNA, ngokuthi kuguquka. Kungaba neze kuthinte isakhiwo amaprotheni, futhi angenza ngokuphelele impahla yayo. Ngakho, ngeke kube khona umonakalo omkhulu zendawo nezomhlaba wonke ka ushintsho olunjalo.

Ngu ngokwabo, ukuguqulwa kwezakhi zofuzo kungase kube pathogenic, okungukuthi ibonakaliswe njengeyenziwe isifo noma ezibulalayo, singavumeli umzimba ukuthuthukisa kusimo iphila. Kodwa iningi izinguquko lutho kumuntu. Okususiwe duplications njalo uzibophezele ezikuyi-DNA, kodwa musa kuthinte inkambo yokuphila komuntu ngamunye.

Ukusulwa - ukulahlekelwa chromosome esifundeni equkethe ulwazi oluthile. Ngezinye izikhathi lezi zinguquko okunenzuzo ukuba umzimba. Asiza kuye uvikele ubudlova zangaphandle, ezifana human immunodeficiency virus namagciwane zihlupha.

Zokunyathelisa - a kabili esifundeni chromosome, futhi kungakho iqoqo izakhi zofuzo okuyinto liqukethe, ibuye kabili. Ngenxa ukuphindaphindwa kolwazi, singaphansi zizalela kancane, futhi ngenxa yalokho ngeke buthelela ukuguquka kwezakhi zofuzo nokushintsha komzimba ngokushesha.

izakhiwo isakhi sofuzo

Umuntu ngamunye unendawo enkulu molecule ye-DNA. Zofuzo - iyunithi obusebenzayo phakathi oyiyo. Kodwa ngisho lezi zindawo ezincane izakhiwo zazo ezihlukile ezivumela ukugcina ukuzinza ekuphileni organic:

1. Readability - ikhono akuhlangani lokhu ngezakhi ezingamaqoqo.
2. Ukuzinza - kulondolozwe isakhiwo kanye izakhiwo.
3. Lability - ikhono ukushintsha ngaphansi kwethonya kwezimo, ukuzivumelanisa ezingezinhle.
4. allelism Multiple - khona ngaphakathi-DNA yezakhi zofuzo okuyinto, ikhodi amaprotheni efanayo isakhiwo ezahlukene.
5. Allelic - kunezinhlobo ezimbili eyodwa izici zofuzo.
6. Ngokucacile - omunye uphawu = eyodwa isakhi esithile sisebenza ngofuzo.
7. Pleiotropy - kaningi imithelela isakhi esisodwa.
8. Expressivity - kobukhulu inkomba okuyinto okubhalwe ngu isakhi sofuzo.
9. Penetrance - imvamisa we genotype e isakhi sofuzo.
10. Okhulisa - okuvela abalulekile inombolo ikhophi isakhi sofuzo ku-DNA.

ufuzo

Ngezakhi zofuzo zomuntu - indaba lonke ngofuzo, okuyinto kuseli eyodwa womuntu. Lokho-ke unikeza isiqondiso ekwakhiweni komzimba, izitho, izinguquko bokuphila. Inchazelo kwethemu yesibili ibonisa isakhiwo umqondo, kunokuba umsebenzi. Ngezakhi zofuzo zomuntu - iqoqo nesidoda okunikelwe phama isethi haploid wama-chromosomes (23 ngazimbili) futhi ezihlobene uhlobo oluthile.

Ngesisekelo ufuzo kuyinto molecule ye-deoxyribonucleic acid kahle owaziwa nge-DNA. Zonke genomes kuqukathe okungenani ezimbili izinhlobo zolwazi: ukwaziswa kwesimiso sezakhi isakhiwo zishintshe umlamuli (okubizwa ngokuthi i-RNA) namaprotheni (lolu lwazi oluqukethwe zofuzo), kanye imiyalelo ukuchaza isikhathi kanye nendawo nokuboniswa lolu lwazi ukuthuthukisa umzimba. Zofuzo ngokwabo hlala ingxenye encane ufuzo, kodwa isisekelo salo. Lokhu kwaziswa okurekhodiwe ezakhini zofuzo - uhlobo Umhlahlandlela ukwenziwa amaprotheni, ngezici eziyisisekelo zokwakheka ilungu elithile lomzimba wethu.

Nokho, okwesikhathi kwebalingisi ephelele ufuzo insufficiently ifakwe kulo ulwazi mayelana nokwakheka amaprotheni. Udinga ulwazi olwengeziwe mayelana izingxenye apharathasi yofuzo, okusho iqhaza umsebenzi zezakhi zofuzo alawule inkulumo yabo ngesikhathi zokukhula ezihlukene futhi ezahlukene izimo zokuphila.

Kodwa ngisho nalokhu akwanele ukuzimisela okuphelele ufuzo. Ngenxa kuwo kukhona izakhi anomthelela self-ukukhiqizwa kabusha yayo (ukufanisana), icwecwe iphakethe DNA nucleus, ngisho abanye kodwa ezindaweni eziyinqaba, ngezinye izikhathi obizwa ngokuthi "sobugovu;" (okungukuthi, uma kwabasebenzi bebodwa kuphela). Ngoba konke lokhu izizathu, okwamanje uma kuziwa ufuzo, ngokuvamile kufanele engqondweni isiqalo nesigcino we-DNA kuboniswe chromosome yeseli nuclei wohlobo oluthile eziphilayo, kuhlanganise, yebo, futhi lokhu ngezakhi ezingamaqoqo.

Usayizi kanye nesakhiwo ufuzo

Kunengqondo ukuphetha ngokuthi isakhi sofuzo, isakhi sofuzo, chromosome kuhlukile abameleli ezahlukene lwezinto eziphilayo emhlabeni. Zingaba mncane ngokungenamkhawulo futhi omkhulu futhi aqukethe izigidigidi ngazimbili lokhu ngezakhi ezingamaqoqo. Sakhiwo isakhi sofuzo uyophinde zincike ngabe uhlole kabani ufuzo.

Ngu lihlela isilinganiso phakathi kwama ubukhulu zofuzo kanye nenani ilungu layo izakhi zofuzo amakilasi amabili ungabahlukanisa:

1. genomes Compact ukuthi akuzona elisekela angaphezu kwezigidi ezingu eziyishumi. Sinenkosi iqoqo izakhi zofuzo kakhulu kuhlobene nezinga ngosayizi. Isici iningi amagciwane prokaryotes.
2. genomes Olubanzi aqukethe angaphezu kwezigidi ezingu-100 base ngazimbili, abangenalo ubudlelwano phakathi ubude bawo futhi nenombolo lokhu ngezakhi ezingamaqoqo. Kwande eukaryotes. Iningi ukulandelanisa nucleotide kuleli kilasi musa encode amaprotheni noma RNA.

Ucwaningo luye lwabonisa ukuthi kukhona mayelana 28.000 zofuzo zofuzo lomuntu. Basuke Ukuboshelwa basakaza yonkana-chromosome, kodwa ukubaluleka lesi sici usalokhu uyimfihlakalo ososayensi.

chromosome

Ngokuvamile ama-chromosome - indlela isembozo izinhlayiya eziyisisekelo zofuzo. Zitholakala Kuyi-nucleus amaseli eukaryotic, futhi ngamunye siqukethe eyodwa-molecule eside kakhulu-DNA. Bona kungabonakala kalula e-microscope ukukhanya enqubeni ukuqoqwa. Karyotype ibizwa ngokuthi isethi ephelele wama-chromosomes, okuyinto ethize uhlobo ngalunye. izakhi okuphoqelekile ngabo kukhona centromere, telomere futhi ukufanisana iphuzu.

Izinguquko wama-chromosomes ngesikhathi cell division

Gene, ufuzo, chromosome - ebisolwa ukuthumela idatha wesifunda amayunithi, lapho ngamunye kuhlanganisa owedlule elandelayo. Kodwa nezinguquko ezithile ukuphila esitokisini. Ngokwesibonelo, e-interphase (phakathi izigaba) kuma-chromosome nucleus ahlelwe alengayo, isikhala esiningi up.

Lapho ingqamuzana silungiselela mitosis (m. E. Ukuze inqubo ukwahlukana amabili), i-chromatin uba futhi osontekile ku-chromosome, futhi manje-ke kuyabonakala microscope ukukhanya. Ngo metaphase Ama-chromosomes e zifane izinduku ngokufanele eduze komunye nomunye futhi uxhumeke kwi-constriction eyinhloko noma centromere. Kuyinto ukwakheka uthi lokuphotha mitotic, lapho iqembu kuma-chromosome iyahambelana. Kuye indawo centromere, kukhona ngezigaba wama-chromosomes:

1. Acrocentric - e Kulokhu, centromere itholakala akuhambisani maqondana maphakathi chromosome.
2. Submetacentric lapho emahlombe (okungukuthi, ezingalawulwa ngaphambi nangemva centromere) engalingani.
3. Metacentric uma centromere uhlukanisa chromosome ncamashi phakathi.

Lokhu kuhlukaniswa ka-chromosome kwahlongozwa ngo-1912 futhi isetshenziswa izazi zezinto eziphilayo kuze kube namuhla.

chromosome anomalies

Njengoba nezinye izakhi morphological a eziphilayo, ama-chromosome futhi kungenzeka izinguquko ezihlelekile ezithinta umsebenzi wabo:

1. Aneuploidy. Lolu shintsho e lonke inani lezakhi zofuzo the karyotype ngokungeza noma ukhipha omunye wabo. Imiphumela yokwanda koshintsho ingaba yingozi lapho iphuzwa ngokweqile ezingenzeka embungwini ongakazalwa, kodwa futhi abangele kwasekuzalweni.
2. Polyploidy. Kubonakaliswa njengoba okwandisa inani lezakhi zofuzo, isigamu amaningi inombolo yawo. Ngokuvamile ezitholakala izitshalo, ezifana ulwelwe nesikhunta.
3. aberrations Chromosomal, noma ukwakha kabusha, - ushintsho isakhiwo chromosome ngaphansi kwethonya yizici zemvelo.

zofuzo

Ufuzo - isayensi study imithetho ufuzo futhi ukushintshashintsha, kanye nokuqinisekisa izindlela oyizalayo. Ngokungafani nezinye eziningi wesayensi yezinto eziphilayo-ke kusukela yaqala, ke uye wafuna ukuba isayensi ngqo. Lonke umlando zofuzo - indaba yokudalwa kanye nokusebenzisa izindlela kakhudlwana futhi esinembile futhi izindlela. Imibono nezindlela zofuzo zifeza indima ebalulekile kwezokwelapha, ezolimo, ukushintshwa kwezakhi zofuzo-microbiology umkhakha.

Ufuzo - ikhono lomzimba ukunikeza ochungechungeni embili kwabangalingani ngeminyaka ye izici morphological, kwamakhemikhali bokuphila kanye nezici. Ngo inqubo ifa kudlalwa ezinkulu zinhlobo eqondene, iqembu (yobuhlanga, labantu) kanye izici umndeni isakhiwo kanye nokusebenza eziphilayo futhi ontogeny yabo (ukuthuthukiswa ngamunye). Akukhona nje ngofuzo izici ezithile kwesakhiwo obusebenzayo umzimba (izici zobuso, ezinye izici izinqubo umzimba, Ubumnene et al.), Kodwa futhi izici physicochemical we owakheke ngayo nosebenza ngayo iseli eziyisisekelo biopolymers. Variability - ezihlukahlukene izimpawu phakathi kwezinhlobo ezithile, kanye impahla inzalo ka ukuthenga sihluke amafomu sabazali. Variability nge ufuzo kukhona izakhiwo ezimbili nolimi yezinto eziphilayo.

Down Syndrome

Down Syndrome - isifo esidluliselwa ngofuzo lapho karyotype siqukethe 47-chromosomes e-womuntu kunokuba senze ngendlela evamile 46. Lokhu kuwuhlobo aneuploidy, njengoba kushiwo ngenhla. Esikhathini pair amabili nanye wama-chromosomes kukhona extra okusenza ulwazi olwengeziwe zofuzo zofuzo lomuntu.

Igama layo syndrome yethiwa udokotela, Don Down, owathola futhi wayichaza izincwadi njengendlela uhlobo isifo sokuphazamiseka kwengqondo ngo-1866. Kodwa ngemuva zofuzo kwatholakala eminyakeni cishe eyikhulu kamuva.

lwezifo

Okwamanje, i-karyotype wama-chromosomes 47 abantu kwenzeka once in a izinsana ayizinkulungwane (phambilini obuwaziwa ngo Izibalo kwakuhlukile). Lokhu kwenziwa Sibonga kungenzeka ukuba ekuhlonzweni lokhu egunjini lokuhlolwa kwezifo. Lesi sifo akuxhomekile sobuhlanga, ubuzwe noma unina isimo sakhe sezenhlalo. Bethonywe ubudala. Amathuba okuba ingane ene-Down syndrome inyuka ngemva iminyaka engamashumi amathathu nanhlanu, futhi ngemva amane Ingxenye banezingane eziphile kahle iziguli alinganayo kakade ku-20 kuya 1. yobudala uyise phezu engamashumi amane futhi kwandisa amathuba okuba ingane nge aneuploidy.

Indlela i-Down Syndrome

Okuvame kakhulu okufana - ukuvela-chromosome eyengeziwe umbhangqwana amabili nanye ngendlela non-sitholwa njengefa. Kuyinto ngenxa yokuthi phakathi ambalwa meiosis akusho ziphikisana ekutheni uthi lokuphotha division. amaphesenti ayisihlanu amacala waphawula mosaicism (chromosome eyengeziwe iqukethe akubona bonke emangqamuzaneni omzimba). Ndawonye akha amaphesenti asithoba anamihlanu we inamba isiyonke yabantu nale isici azalwa nako. Labo abasele abanga-amaphesenti ayisihlanu syndrome ibangelwa trisomy lezinceku chromosome amabili nanye. Nokho, ukuzalwa kwezingane ezimbili nalesi sifo emkhayeni efanayo kancane kuphela.

umtholampilo

Umuntu abane-Down syndrome kungenziwa obonwa isici izici zangaphandle, nazi ezinye zalezi zizathu:

- isicaba ubuso;
- a mfushane skull (ubukhulu transverse njengengcebo enkulu kunemicebo longitudinal);
- isikhumba nesibaya entanyeni;
- emphethweni isikhumba ukuthi ihlanganisa ekhoneni engaphakathi iso;
- Ukuhamba ngokweqile amalunga;
- kwehle imisipha ithoni;
- aba we ngemuva ekhanda;
- nemilenze iDemo neminwe;
- ukuthuthukiswa esweni ezinganeni abaneminyaka engama ayisishiyagalombili;
- anomalies amazinyo nolwanga;
- yesifo senhliziyo azalwa naso;
- kungahle kube syndrome sokuwa;
- wegazi.

Kodwa kusobala ukuthi uphethwe isekelwe kuphela ukubonakaliswa kwangaphandle Yiqiniso, akunakwenzeka. Kudingekile karyotyping.

isiphetho

Gene, isakhi sofuzo, chromosome - kubonakala sengathi kungcono nje izwi lakhe incazelo siyaqonda ndawonye futhi ukude kakhulu. Kodwa eqinisweni, ezisithintayo kakhulu ezimpilweni zethu futhi ukushintsha, futhi siyaphoqeleka ukuba ashintshe. Le ndoda uyazi ukuthi ukuzivumelanisa nezimo, babe yini, ngisho kubantu abane kwezinso zofuzo kukhona njalo isikhathi nendawo lapho iyolondeka khona Irreplaceable.