Kuyini i-chromosome? Setha lezakhi zofuzo. Ipheya-chromosomes

Ufuzo futhi kokuhlukana ngokwemvelo zikhona ngoba, izakhi zofuzo, ama-chromosome deoxyribonucleic acid (DNA). Izitolo futhi adlulisele ukwaziswa kwezakhi zofuzo ngesimo amaketango nucleotide e-DNA. Iyiphi indima kule mkhuba kungokwalabo ezakhini zofuzo? Kuyini i-chromosome ngokuya ukudluliswa zezici esiwufuzo? Izimpendulo zale mibuzo ngeke baqonde izimiso ka esephepheni kanye ukwehluka zofuzo eplanethini yethu. Ngokwezinga elikhulu incike indlela chromosome kakhulu engena isethi, kusukela recombination zalezi zakhiwo.

Kusukela umlando kuvulwa "ufuzo kuyizinhlayiyana"

Ukutadisha ngaphansi ngesibonakhulu amaseli zezitshalo nezilwane, zezitshalo eziningi Izazi namanje phakathi kwekhulu XIX, yabhekisela imicu abachwepheshile kulencane annular isakhiwo nucleus. Ngokuvamile kunamanye Ama-chromosomes e ngokuthi iphayona we anatomist German Walther Flemming. Lokho wasebenzisa aniline udayi ukubhekisiswa izakhiwo zenuzi. Fleming wathola into okuthiwa "chromatin" ngoba ikhono lakhe staining. Igama elithi "chromosome" Ngo-1888, kwangenisa inguquko yesayensi Genrih Valdeyer.

Ngesikhathi esifanayo Flemming wayefuna impendulo yombuzo othi lokho chromosome, eBelgian Edouard Van Beneden. Kancane ngaphambili sezinto eziphilayo German Theodor Boveri no-Eduard Strasburger olwenziwa uchungechunge ucwaningo ukufakazela ukuthi singobani-chromosomes, le ukuqinisela inombolo yabo kwezinhlobo ezahlukene eziphilayo.

INGEMUVA chromosomal imfundiso yokuziphendukela ufuzo

isazi American Walter Sutton wathola angabi nezakhi zofuzo eziningi kanjani ezitholakala le kuyi-nucleus yengqamuzana. Usosayensi babekholelwa isakhiwo amayunithi ukwesekwa ufuzo izici umzimba. Sutton wathola ukuthi chromosomes e aqukethe izakhi zofuzo, lapho zize zidlulele abazali inzalo izakhiwo kanye nemisebenzi. Isazi sesayensi yezakhi zofuzo ezincwadini wachaza ngazimbili chromosome, ukunyakaza kwabo ngesikhathi division of the kuyi-nucleus yengqamuzana.

Kungakhathaliseki ozakwabo American, ukusebenza luhamba luye ohlangothini olulodwa wahola Theodor Boveri. Bobabili abacwaningi emisebenzini wafunda nezindaba lokwedlulisela izici ngofuzo, zavela amalungiselelo eziyisisekelo ngendima-chromosomes (1902-1903). ukuqhubeka theory Boveri-Sutton esenzeka laboratory kaNobel Thomas Morgan. Eminent sezinto eziphilayo American nethimba lakhe sezisungule uchungechunge imithetho ukubeka izakhi zofuzo ku-chromosome, siye ithuthukiswe ngesisekelo cytological echaza inqubo nemithetho Gregor Mendel - uyise ekusungulweni zofuzo.

I-chromosomes e-cell

Ukuphenywa isakhiwo wama-chromosomes waqala ngemva kokutholakala kanye nencazelo kwekhulu XIX. Lezi corpuscles futhi sesigcilikisha eziqukethwe eziphilayo prokaryotic (non-senuzi) namaseli eukaryotic (nucleus). Ukutadisha ngaphansi ngesibonakhulu wembula ukuthi le-chromosome iphuzu morphological umbono. Le ndikimba filamentous mobile, okuyinto ukubonakala ngezigaba ezithile umjikelezo cell. Yonke umthamo chromatin interphase nucleus ithatha. Ngamanye nezikhathi chromosome akachazeki Gxila kokukodwa noma okubili chromatids.

Kungcono wazibona lezi zokwakheka ngesikhathi cell division - mitosis noma meiosis. Ngo amaseli eukaryotic ngokuvamile ungakwazi bagcine-chromosomes ezinkulu isakhiwo komugqa. Ngo prokaryotes, mancane, nakuba zikhona ezehlukile. Amaseli ngokuvamile zihlanganisa nezinhlobo ezingaphezu kweyodwa hlobo Ama-chromosomes e, isibonelo yabo encane "izinhlayiya ifa" ungaphakathi mitochondria futhi chloroplast.

ifomu-chromosomes

I-chromosome ngayinye has a isakhiwo ngabanye, ihlukile kwezinye izici staining. Ekuhloleni morphology kubalulekile ukunquma isikhundla centromere, ubude nokubekwa izingalo isihlobo ukuba nokhalo. Isethi wama-chromosomes ngokuvamile yakhiwa amafomu alandelayo:

• metacentric noma-alinganayo, elinesimo indawo phakathi centromere;
• submetacentric noma neravnoplechie (constriction is offset maqondana omunye telomers);
• acrocentric, noma induku emise, lapho centromere itholakala cishe ekupheleni Ama-chromosomes e;
• ka ukhombe nge ukuma neze definable.

chromosome umsebenzi

Ngokuvamile ama-chromosome yakhiwa izakhi zofuzo - amayunithi obusebenzayo ufuzo. Telomere - emikhawulweni izingalo chromosome. Lezi zici ezikhethekile ukukhonza for nokuvikelwa uma umonakalo, antiblock izinsalela. Centromere wenza imisebenzi yayo nge kabili kuma-chromosome. It has a kinetochore, nguye ukukhwezwa isakhiwo uthi lokuphotha. Ngalinye pair of-chromosomes kuyinto ngabanye endaweni indawo centromere. Sesigcilikisha ukusebenza othini lokuphotha ukuze amaseli indodakazi ubabonisa kwenye chromosome, kodwa hhayi kokubili. ukubuyelela kabili Uniform enqubeni ukuqoqwa inikeza umsuka ukufanisana. Zokunyathelisa chromosome ngayinye iqala kanyekanye ezindaweni eziningana yokuthi ngokuphawulekayo ngesivinini lonke inqubo yokuhlukanisa.

Indima of DNA ne-RNA

Ukuze uthole ukuthi yini i-chromosome, okuyinto umsebenzi kulesi sakhiwo zenuzi kuhlulekile ngemva kokutadisha ngezithako zawo kwamakhemikhali kanye izakhiwo. Ngo amaseli eukaryotic, ama-chromosome yenuzi akhiwa impahla tho - chromatin. Ngokwe-ukuhlaziywa, liphethe okusezingeni eliphezulu isisindo yamangqamuzana izinto eziphilayo:

• Deoxyribonucleic acid (DNA);
• ribonucleic acid (RNA);
• histone amaprotheni.

acid nucleic zithatha ingxenye ngokuqondile biosynthesis amino acid kanye namaprotheni ezinikeza ukudluliswa nezakhi zofuzo ezizukulwaneni ngezizukulwane. DNA eziqukethwe kuyi-nucleus ye amaseli eukaryotic, RNA bagxila kule cytoplasm.

zezakhi zofuzo

-X-ray ukuhlaziywa wabonisa ukuthi i-DNA yakha Kuvunguza double, okuyinto aqukethe uchungechunge ama-nucleotide. Zimelela a deoxyribose carbohydrate, iqembu phosphate futhi omunye kwezisekelo ezine-nitrogen:

1. A - i-adenine.
2. G - i-guanine ne.
3. T --thymine.
4. C - cytosine.

Lots dezoksiribonukleoproteidnyh sesigcilikisha Helical - a izakhi zofuzo ethwele ukwaziswa kwesimiso sezakhi mayelana ukulandelana amino acid amaprotheni noma RNA. Phakathi ukuphindwaphindwa nezakhi zofuzo kubazali enzalweni idluliselwa ngendlela isakhi sofuzo alleles. Yizo ezinquma ukusebenza, ukukhula nokuthuthuka ephilayo ethile. Abanye abacwaningi bathi, kulezo zindawo DNA musa encode polypeptides imisebenzi zokulawula. Ufuzo kubantu kungase kudingeke kuze kufinyelele ayizinkulungwane ezingu-30. Zofuzo.

setha wama-chromosomes

Inani lezakhi zofuzo, izici zabo - isici isici ifomu. Ngo impukane Drosophila inombolo yabo - 8, e wezinkawu - 48, umuntu - 46. Le nombolo kuyinto njalo amaseli eziphilayo yilunga zohlobo olufanayo. Ukuze zonke eukaryotes kukhona welithi "Ama-chromosomes e diploid." Lokhu isethi ephelele, noma 2N, ngokungafani haploid - isigamu lemali (n).

Ngokuvamile ama-chromosome yakhiwa yebhangqa homologous, nesimo esifanayo, isakhiwo, indawo centromere, nezinye izakhi. Homologues anezici zabo ukuthi kwehlukaniswe nezinye-chromosomes e isethi. Staining nge udayi eziyisisekelo Kusinikeza nethuba lokucabangela, ukuhlola izici esasenza pair ngamunye. Ama-chromosomes e Diploid elikhona ukuphathwa kwabathintwayo amaseli haploid esifanayo - in the lwegciwane (okubizwa ngokuthi gametes). Ngo ezincelisayo kanye nezinye izinto eziphilayo ubulili heterogametic besilisa kwakhiwa izinhlobo ezimbili-chromosomes ubulili: X chromosome futhi Y. Amaduna abe iqoqo XY, nabesifazane - XX.

Human chromosome isethi

omzimba womuntu aqukethe Ama-chromosomes e-46. Bonke ehlangana ngazimbili 23 ezakha iqoqo. Kunezinhlobo ezimbili zama-wama-chromosomes autosomes futhi ngihlanganyele ubulili. Eyokuqala ifomu 22 ngazimbili - zivamile besilisa nabesifazane. Basuke izimpawu umbhangqwana 23 - ucansi-chromosomes, okuyizinto emangqamuzaneni omzimba besilisa non-homologous.

izici zofuzo elihlobene ne ubulili. Ukuze ukudluliswa kukhona Y no-X chromosome kwabesilisa, ezimbili X abesifazane. Autosomes aqukethe lonke ulwazi mayelana nezakhi zofuzo. Kukhona amasu evumela ngezifiso wonke amapheya 23. Zibonakala kahle izibalo, lapho ababethi umbala othize. Kungokuphawulekayo ukuthi incwadi 22-chromosome e okusha ngezakhi zofuzo zomuntu - kulencane kakhulu. Its iDNA welulela isimo has a ubude 1.5 cm, futhi 48 kwezigidi ezingu namabhuzu nitrogen elisekela. Special amaprotheni histones kusukela chromatin enze kokucindezelwa, bese intambo kuthatha indawo encane izikhathi ezingaba yinkulungwane kuyi-nucleus yengqamuzana. Ngesibonakhulu electron, le histones nucleus interphase zifane ubuhlalu, ahlukaniswe ku umucu DNA.

izifo zofuzo umuntu

Kunezinhlobo ezingaphezu kuka-ayizinkulungwane ezintathu. Izinhlobo ezahlukene izifo lezinceku kubangelwa umonakalo neziyaluyalu kuma-chromosome. Lezi zihlanganisa i-Down Syndrome. Uma umntwana isifo esidluliselwa ngofuzo libhekene ukubambezeleka ukuthuthukiswa engqondweni nasemzimbeni. Ngo-cystic fibrosis kukhona ukwehluleka in the imisebenzi exocrine nezindlala. Ukwephulwa kuholela yezinkinga ukujuluka, ukukhululwa kanye ekuqongeleleni isikhwehlela emzimbeni. Kwenza kube nzima ukusebenza kwamaphaphu kungaholela ukuphefumula nobunzima nokufa.

Ukwephula imibala - ubumpumputhe - amasosha omzimba ukuba izingxenye ezithile bohlu umbala. Hemophilia kuholela buthakathaka ekunqandeni igazi. zokungezwani ne-lactose ayivumeli umzimba womuntu ukugaya ubisi noshukela. Ngo-ofisini zokuhlela umndeni ingatholakala kwi nezici ezithile ukuze isifo esithile zofuzo. In izikhungo ezinkulu zokwelapha nethuba lokuthola kokuhlaziywa ezifanele kanye nokwelashwa.

Ukwelashwa kwezakhi zofuzo - isiqondiso imithi yanamuhla, elucidation we izakhi zofuzo ezibangela izifo zenani elikhulu eziyifa kanye nokuqedwa yayo. Nge amasu zakamuva amaseli sokugembula esikhundleni okhathazekile iqondiswa izakhi zofuzo evamile. Kulokhu, odokotela abazange akhulule ngesineke izimpawu, kanye nezizathu sifo. Ukulungiswa Kwenziwa kuphela ukuphathwa kwabathintwayo yokwelapha cell isakhi sofuzo ayikahlanganiswa kunonophiswe kubuye kusetshenziswe maqondana amaseli ngokobulili.