Izinguquko ze-Gene zihlotshaniswa nezinguquko kwinombolo nesakhiwo sama-chromosomes

Ukulinda ukuzalwa kwengane yisikhathi esihle kunazo zonke kubazali, kodwa futhi kukhona okubi kakhulu. Abaningi bakhathazeka ngokuthi ingane ingazalwa nganoma yimaphi amaphutha, ukukhubazeka ngokomzimba noma kwengqondo.

Isayensi ayimi, kunethuba lokuhlola ukukhulelwa okuncane kwengane ngokuphambuka kwentuthuko. Cishe zonke lezi zivivinyo zingabonisa ukuthi konke okujwayelekile kumntwana.

Kungani kwenzeka ukuthi abazali abafanayo bangazalwa ngokuphelele izingane ezahlukene - ingane enempilo nengane ekhubazekile? Lokhu kunqunywa yizakhi zofuzo. Ekuzalweni kwengane engaphili kahle noma ingane ekhubazekile ngokomzimba, ukushintshashintsha kwezakhi zofuzo ezihambisana nokuguquka kwesakhiwo se-DNA kuthinteka. Ake sikhulume ngalokhu ngokuningiliziwe. Cabanga ukuthi lokhu kwenzeka kanjani, yiziphi izakhi zofuzo ezishintshayo, nezimbangela zabo.

Yini izinguquko?

Izinguquko zinguquko zomzimba nezemvelo emangqamuzaneni okwakhiwa kwe-DNA. Isizathu singase sibe yi-irradiation (ngesikhathi sokukhulelwa, awukwazi ukuthatha izithombe ze-X ray, ukulimala kanye nokwahlukana), imisebe ye-ultraviolet (ukuvuleka isikhathi eside elangeni ngesikhathi ukhulelwe, noma ukuhlala egumbini elinama-ultraviolet lights). Futhi ukuguqulwa okunjalo kungadluliselwa futhi kuzuzwe njengefa. Zonke zazo zihlukaniswe zibe izinhlobo.

Izinguquko ze-Gene nezinguquko esakhiweni sama-chromosomes noma inombolo yabo

Izinguquko ze- Chromosomal ziyashintsha lapho isakhiwo nesibalo se-chromosome kuguqulwa khona. Ama-patches e-Chromosomal angawa noma aphindwe kabili, athuthela endaweni engezona-homological, asuka esimweni esivamile ngamagreyidi ayikhulu namashumi ayisishiyagalolunye.

Izizathu zokubonakala kwenguquko enjalo ukuphulwa ekudluleleni.

Ukushintshashintsha kwe-gene kuhlotshaniswa nezinguquko esimweni se-chromosomes noma inombolo yakhe, yimbangela yezifo ezibucayi nezifo ezinganeni. Izifo ezinjalo azipheli.

Izinhlobo zezinguquko ze-chromosome

Kunezinhlobo ezimbili zezinguquko eziyisisekelo ze-chromosomal: izinombolo nezakhi. I-Aneuploidy yizinhlobo zezinhlobo ze-chromosomes, okungukuthi, uma ukuguqulwa kwezakhi zofuzo kuhlotshaniswa noshintsho kwinombolo yama-chromosomes. Lokhu kuvela kokunye okunye noma okunye okulandelayo, ukulahlekelwa yiyiphi yazo.

Ukushintshashintsha kwe-gene kuhlotshaniswa noshintsho kwisakhiwo lapho ama-chromosomes ephuka, bese ehlangana futhi, ephazamisa ukumiswa okujwayelekile.

Izinhlobo ze-Chromosomes Numerical

Ngokusho kwenani lama-chromosomes, ukuguqulwa kwezinto eziguquguqukayo kuhlukaniswe nge-aneuploidy, okungukuthi, izinhlobo. Cabanga ngokuyinhloko, sizothola umehluko.

• I-Trisomy

I-Trisomy ibonakala ku-karyotype ye- chromosome eyengeziwe. Into ejwayelekile kunazo zonke ukubonakala kwe-chromosome engamashumi amabili nanye. Iba imbangela ye-Down's syndrome, noma, njengoba kubizwa lesi sifo, i-trisomy ye-chromosome engamashumi amabili nanye.

I-Patau syndrome ibonakala yi-thirteen, kanti i-chromosome yeshumi nesishiyagalombili iyatholakala ukuthi i- Edwards syndrome. Lawa wonke ama-trisomie we-autosomal. Okunye i-trisomy ayikwazi ukusebenza, ifa esibelethweni futhi ilahlekile ngokukhipha isisu okuzenzakalelayo. Labo bantu abane-chromosomes eyengeziwe yobulili (X, Y) - bayasebenza. Ukubonakaliswa kwemitholampilo yokuguquka okunjalo kuncane kakhulu.

Izinguquko ze-Gene ezihambisana nokushintsha kwenombolo zivela ngezizathu ezithile. I-trisomy kaningi ingenzeka uma ama- chromosomes ehlukanisa ama- homologous ku-anaphase (meiosis 1). Umphumela walokhu kungavumelani ukuthi ama-chromosomes womabili angena kuphela kweyodwa yamaseli amantombazane amabili, okwesibili alinalutho.

I-chromosomes engavamile ingahle ivele njalo. Lesi simo sibizwa ngokuthi ukwephulwa kokuhlukana kwama-chromatids odade. Ivela ku-meiosis 2. Yilokho kanye lapho ama-chromosomes amabili aphelele ahlala ku-gamete eyodwa, edala i-zygote ye-trisomic. I-nondisjunction ivela ezinyathelweni zakuqala zenqubo yokuchoboza iqanda eliye lakhulelwa. Ngakho-ke, i-clone yama-mutant cells ivela, engakwazi ukumboza ingxenye enkulu noma encane yezicubu. Ngezinye izikhathi kubonakala ngokusemtholampilo.

Abaningi bahlobanisa i-chromosome engamashumi amabili nanye ubudala ngenkathi owesifazane okhulelwe, kodwa lesi sici kuze kube yilolu suku asinaso isiqiniseko esingavumelekile. Izizathu zokuthi kungani ama-chromosomes engahambisani nawo awaziwa.

• I-Monosomy

I-monosomy yikungabikho kwe-autosomes. Uma lokhu kwenzeka, ezimweni eziningi ingane ayikwazi ukukhishwa, ukubeletha ngaphambi kwesikhathi kwenzeka ezinyathelweni zokuqala. Okuhlukile kuyisimo esiyingqayizivele ngenxa ye-chromosome engamashumi amabili nanye. Isizathu sokubonakala kwe-monosomy kungase kube ukungafani kwama-chromosomes, nokulahlekelwa kwe-chromosome phakathi nenkambo yayo ku-anaphase esitokisini.

Ema-chromosomes ezocansi, i-monosomy iholela ekusungulweni kwe-fetus, lapho i-karyotype i-XO. Ukubonakaliswa kwemitholampilo ye-karyotype enjalo yi-Turner's syndrome. Emaphesenti angamashumi ayisishiyagalombili amacala avela kwekhulu, ukubonakala kwe-monosomy kwi-X chromosome kungenxa yokuphulwa kwe-meiosis yengane. Lokhu kubangelwa ukungalingani kwama-chromosomes we-X ne-Y. Ngokuyinhloko, ingane ephethe i-KO karyotype ibulawa esibelethweni.

Ku-chromosomes ocansi, i-trisomy ihlukaniswe yaba izinhlobo ezintathu: 47 XXY, 47 XXX, 47 i-XYY. I-Klinefelter's syndrome i-trisomy 47 i-XXY. Nge-karyotype enjalo, amathuba okubeletha abantwana angama-50 kuya ku-50. Isimbangela sesifo esinjalo singaba ukungahlukanisi kwama-chromosomes e-X noma okungezona ukujula kwe-X ne-Y ye-spermatogenesis. I-karyotypes yesibili nowesithathu ingabanjwa kuphela kwabesifazane abayizinkulungwane ezikhulelwe, cishe abazibonakali ngokwabo futhi ezimweni eziningi zitholwa ochwepheshe ngempela engozini.

• Polyploidy

Lezi zinguquko zakhi zofuzo ezihambisana nokuguquka kweqoqo lama-chromosomes. Lezi zihloko zingaba kathathu futhi ziphindwe kathathu. I-triploidy ivame ukutholakala kuphela uma kukhishwa isisu. Kwakukhona amacala amaningana lapho umama engakwazi ukubekezelela ingane enjalo, kodwa bonke bafa ngaphambi kokufinyelela enyangeni eyodwa. Izindlela zokushintshashintsha kwezakhi zofuzo uma kwenzeka i-triploidy zibangela ukuhlukana okuphelele nokungafani kwazo zonke izigcawu ze-chromosomal zezinsikazi zesilisa noma zesilisa. Futhi, le ndlela ingaba ukukhulelwa kabili kweqanda elilodwa. Kulesi simo, i-placenta iyancipha. Ukuzalwa kabusha okunjalo kubizwa ngokuthi i-bubble drift. Njengomthetho, izinguquko ezinjalo ziholela ekuthuthukiseni ukukhathazeka kwengqondo nengokwenyama yengane, ukuqedwa kokukhulelwa.

Iziphi izakhi zokuguqula izakhi ezihlotshaniswa nezinguquko kwisakhiwo se-chromosome

Izinguquko ezakhiweni zama-chromosomes ziwumphumela wokuqedwa (ukubhujiswa) kwe-chromosome. Ngenxa yalokho, la ma-chromosomes ahlangana, aphule ukubonakala kwawo kwangaphambili. Lezi zinguquko zingase zingalingani futhi zilinganise. Ukulinganisela akudingeki ukuchitha noma ukungabi nalutho, ngakho ungabonisi. Angabonakala kuphela kulawo mahlakalo, uma kukhona isakhi esakhiweni sokubhujiswa kwe-chromosome, ebaluleke kakhulu. Ngesethi elinganisiwe, ama-gametes angabonakala engalingani. Ngenxa yalokho, ukukhulelwa kwe-ovum ene-gamete enjalo kungaholela ekubukeni kwe-fetus ngesethi ye-chromosome engalingani. Njengoba isethi esinjalo, i-fetus inenqwaba yeziphambeko zentuthuko, izinhlobo ezinzima ze-pathology zivela.

Izinhlobo zokuguqulwa kwesakhiwo

Izinguquko ze-Gene zenzeka ezingeni lesakhiwo se-gamete. Akunakwenzeka ukuvimbela le nqubo, futhi ngeke ukwaziwa ukuthi izinguquko ezinjalo zingenzeka. Kunezinhlobo eziningana zokuguqulwa kwesakhiwo.

• Ukususwa

Lolu shintsho luhlobene nokulahlekelwa yingxenye ye-chromosome. Ngemuva kwekhefu elinjalo, i-chromosome iba yifushane, futhi ingxenye yayo ephukile ilahlekile ngokuhlukana kweselula. Ukususwa kokungena komzimba kuyindaba lapho i-chromosome eyodwa iphulwa kanyekanye ezindaweni eziningana. Ama-chromosomes anjalo avame ukudala isisu esingenakuvikelwa. Kodwa kunezimo lapho izingane zisinda, kodwa ngenxa ye-chromosomes enjalo kune-Wolf-Hirschhorn syndrome, "ukukhala kwekati".

• Izimpendulo

Lezi zakhi zofuzo zenzeke ezingeni lenhlangano yezingxenye ezimbili ze-DNA. Ngokuvamile, ukuphindaphinda akukwazi ukubangela izifo ezinjalo ezibangela ukususwa.

• Izinguquko

Ukuthuthwa kwe-Translocation kungenxa yokudluliselwa kwezakhi zofuzo kusuka kwelinye i-chromosome kuya kwenye. Uma ikhefu livela ngesikhathi esisodwa kuma-chromosomes amaningana futhi baxoxisana ngamagceke, lokhu kubangela ukudluliselwa kwemikhawulo. I-karyotype ye-translocation enjalo ine-chromosomes engamashumi amane nesithupha kuphela. I-translocation efanayo iyavezwa kuphela ngokuhlaziywa okuningiliziwe nokutadisha i-chromosome.

Shintsha ukulandelana kwe-nucleotide

Ukushintshashintsha kwe-gene kuhlotshaniswa nokushintsha kokulandelana kwe-nucleotides, lapho kuboniswa ekuguqulweni kwezakhiwo zezingxenye ezithile ze-DNA. Emiphumeleni yokuguqulwa okunjalo ihlukaniswe yaba izinhlobo ezimbili - ngaphandle kokushintshwa kwesihlaka sokufunda kanye nokushintsha. Ukuze ukwazi kahle izimbangela zenguquko ezifundeni ze-DNA, kubalulekile ukucubungula uhlobo ngalunye ngokwehlukana.

Ukuguqulwa ngaphandle kokushintsha kwesikrini

Lezi zinguquko zakhi zofuzo zihlotshaniswa nokuguqulwa nokuguqulwa kwamabhuloki e-nucleotide kwisakhiwo se-DNA. Ngokungena esikhundleni esinjalo, ubude be-DNA abulahlekile, kodwa ukulahlekelwa nokushintshwa kwama-amino acids kungenzeka. Kukhona kungenzeka ukuthi isakhiwo seprotheyini sizogcinwa, lokhu kuzoba ukukhubazeka kwekhodi yezofuzo. Ake sicabange ngokuningiliziwe kokubili ukuhlukahluka kwentuthuko: ngokufaka esikhundleni futhi ngaphandle kokushintshwa kwama-amino acids.

Ukuguqulwa ngokushintshwa kwama-amino acids

Ukuguqulwa kwama-amino acid e-polypeptide kubizwa ngokuthi i-missense mutations. Esikhathini samakhemikhali we-hemoglobin kukhona amaketanga amane - amabili "a" (itholakale ku-chromosome yeshumi nantathu) futhi amabili "b" (ikhodi ye-chromosome yeshumi nanye). Uma i- "b" iyinkambo evamile, futhi iqukethe amashiya ayikhulu namashumi amane nesithupha, kanti yesithupha i-glutamine, i-hemoglobin iyoba yinto evamile. Kulesi simo, i-asidi glutamic kufanele ifakwe ikhodi nge-triplet ye-GAA. Uma ngenxa yokuguqulwa kwe-GAA ithathelwe indawo yi-GTA, esikhundleni se-glutamic acid enqamuzaneni le-hemoglobin, i-valine yenziwa. Ngakho, esikhundleni se-hemoglobin HbA evamile, enye i-HbS hemoglobin izovela. Ngakho-ke, ukushintshwa kwe-amino acid kanye ne-nucleotide eyodwa kuzobangela ukugula okubi kakhulu - i-sickle cell anemia.

Lesi sifo sibonakala eqinisweni ukuthi amangqamuzana egazi abomvu ayenokuma, njengesikhala. Kule fomu abakwazanga ukuhambisa i-oksijeni evamile. Uma ama-homozygote ezingeni lamaselula ane-formula HbS / HbS, lokhu kuholela ekufeni kwengane ngesikhathi sokuqala komntwana. Uma ifomula i-HbA / HbS, amaseli egazi abomvu abe nohlobo oluthile lokushintsha. Ukuguqulwa okunjalo obuthakathaka kunemfanelo ewusizo - ukumelana komzimba kumalariya. Kulawo mazwe lapho kunengozi yokubamba i-malaria kufana nokubandayo eSiberia, lolu shintsho luyimfanelo ezuzisayo.

Ukushintshwa ngaphandle kwe-amino acid esikhundleni

Ukushintshwa kwama-nucleotide ngaphandle kokushintshaniswa kwama-amino acids kubizwa ngokuthi i-seymensens. Uma kuyingxenye ye-DNA encoding "b" - uchungechunge kukhona ushintsho lwe-GAA kuya ku-GAG, ngenxa yokuthi i- genetic code in excess, esikhundleni se-glutamic acid asinakwenzeka. Isakhiwo sochungechunge ngeke sishintshwe, ngeke kube khona ushintsho kumaseli obomvu egazi.

Izinguquko ezinokushintshwa kwesakhiwo

Ukuguquka kwezakhi zofuzo kuhlotshaniswa nezinguquko ekude kweDNA. Ubude bungaba buncane noma bukhulu, kuye ngokuthi ukulahlekelwa noma ukuhlanganiswa kwamabhuloki we-nucleotide. Ngakho-ke, isakhiwo sonke seprotheyini sizoguqulwa ngokuphelele.

Ukususwa okungahle kwenzeke kungenzeka. Lokhu kwenzeka uma kunendawo yokuguqulwa kwezinto ezimbili ezibuyisana. Lesi yisikhathi sokunamathiswa kweqembu le-nucleotide ngemuva kokulahlekelwa, futhi ngokufanayo.

Izinguquko ezingenamthetho

Leli qembu elikhethekile lezinguquko. Kubonakala kungavamile, uma kunjalo, ukubonakala kwama-codons okuma kwenzeka. Lokhu kungenzeka kokubili ngokulahlekelwa ngamabhuloki we-nucleotide, futhi ngokunamathiselwe kwabo. Uma umisa ama-codons, ukuhlanganiswa kwe-polypeptides kuyeke ngokuphelele. Ngale ndlela, zero alleles zingenziwa. Akukho namaprotheni azofanisa nalokhu.

Kukhona into enjengokucindezelwa kwangaphakathi. Lena yinto lapho ukuguqulwa kwesakhi esisodwa kuphazamisa ukuguqulwa kwamanye amazwe.

Zikhona yini izinguquko ekukhulelweni?

Izinguquko ze-Gene ezihambisana nezinguquko kwinani lama-chromosomes zingase zinqunywe ezimweni eziningi. Ukuze uthole ukuthi ngabe ingane ikhona yini amaphutha ekuthuthukiseni nasezindaweni zokukhubazeka, ukuhlolwa kunqunywe emavikini okuqala okukhulelwa (amasonto ayishumi neshumi nantathu). Lolu uchungechunge lwezivivinyo ezilula: ucingo lokuhlolwa kwegazi kusuka kumunwe nangomvini, i-ultrasound. Kuhlolwa kwe-ultrasound, i-fetus iphathwa ngokuhambisana nemingcele yazo yonke imilenze, impumu kanye nekhanda. Lezi ziminganiso, ngokungahambisani ngokuqinile nemigomo, kubonisa ukuthi ingane ineziphambeko ekuthuthukisweni. Lokhu ukuxilongwa kuqinisekisiwe noma kunqatshelwe ngenxa yemiphumela yokuhlolwa kwegazi.

Futhi ngaphansi kokuqondiswa okudokotela odokotela bangomama ozayo, abangabantwana babo abangase babe nezinguquko ezingeni lezakhi, abazuze njengefa. Lokhu kungukuthi, laba bangabesifazane ababelethwe yingane ekhubazekile engqondweni noma engokwenyama, ehlolwe nge-Down's syndrome, Patau nezinye izifo zofuzo.