Tag nrho cov khoom siv caj ces tau muab tso rau hauv tsuas yog 46 khub ntawm chromosomes. Thiab chromosomes, raws li peb paub los ntawm biology, nyob rau hauv lub nucleus ntawm lub cell. Tus neeg noj qab haus huv muaj karyotype ntawm 23 khub ntawm diploid chromosomes. Ntawd yog, 46 XX yog poj niam chromosome teeb, thiab 46 XY yog txiv neej chromosome teeb. Thaum chromosome tawg, lub ntsiab "carrier" ntawm caj ces, ntau yam kev ua txhaum cai tshwm sim.
Kev hloov pauv tsis yog tshwj xeeb rau tib neeg. Cov kev hloov me me hauv cov khoom siv caj ces ua rau muaj kev sib txawv ntawm qhov tshwm sim ntawm xwm. Nrog rau qhov sib npaug sib npaug, qhov kev hloov pauv hauv chromosomes tshwm sim yam tsis muaj cov ntaub ntawv poob thiab tsis muaj qhov tsis tsim nyog. Feem ntau qhov no tshwm sim thaum lub sij hawm meiosis (chromosome division), nyob rau hauv tas li ntawd, tej zaum ib feem ntawm chromosomes yog duplicated (duplication tshwm sim), thiab ces qhov tshwm sim yog unpredictable. Tab sis peb tsuas yog xav txog Robertsonian translocations, lawv cov yam ntxwv thiab qhov tshwm sim.
Robertsonian translocations - yog dab tsi? Gene problems of humanity
Vim qhov sib txawvchromosomes nyob ze ntawm lub centromere, cov qauv kev hloov pauv tshwm sim hauv tib neeg txoj cai caj ces. Qhov sib txawv tuaj yeem ua ib leeg, thiab qee zaum rov ua dua. Ib sab caj npab ntawm chromosome tom qab so (feem ntau yog caj npab luv) ploj. Tab sis muaj cov xwm txheej thaum lub sijhawm so tshwm sim ib txhij hauv 2 chromosomes, cov caj npab luv luv uas tau hloov pauv. Nws tshwm sim tias tsuas yog qee qhov ntawm lub xub pwg undergo translocation. Tab sis xws li caj npab luv luv hauv chromosomes ntawm hom acrocentric (nyob rau hauv uas centromere faib cov chromosome rau hauv caj npab ntev thiab luv dua) yeej tsis nqa cov ntaub ntawv tseem ceeb. Tsis tas li ntawd, kev poob ntawm cov ntsiab lus no tsis yog qhov tseem ceeb, vim tias cov ntaub ntawv keeb kwm no tau theej rau hauv lwm cov acrocentric chromosomes.
Tab sis thaum sib cais luv caj npab fuse nrog cov caj npab luv ntawm lwm cov noob, thiab cov caj npab ntev uas tseem tshuav kuj tau sib koom ua ke, ces qhov kev hloov pauv no tsis sib npaug. Xws li "rearrangements" ntawm cov khoom siv caj ces yog Robertsonian translocations.
W. Robertson kawm thiab piav txog hom kev hloov pauv no hauv xyoo 1916. Thiab lub anomaly tau muaj npe tom qab nws. Robertsonian translocation tuaj yeem ua rau muaj mob qog noj ntshav, tab sis yuav tsis cuam tshuam rau cov tsos mob thiab kev noj qab haus huv ntawm tus neeg nqa khoom. Txawm li cas los xij, ib tug me nyuam feem ntau, yog tias ib tug ntawm cov niam txiv muaj xws li kev hloov chaw, yug los nrog kev sib txawv.
Kev hloov pauv ntau npaum li cas?
Ua tsaug rau kev txhim kho thev naus laus zis thiab kev tsim cov noob caj noob ces raws li kev tshawb fawb, niaj hnub no tuaj yeem paub ua ntej seb puas muaj qhov tsis txaus ntseeg hauvkaryotype ntawm tus me nyuam hauv plab. Tam sim no nws muaj peev xwm ua cov txheeb cais: ntau npaum li cas cov noob anomalies tshwm sim? Raws li cov ntaub ntawv tam sim no, Robertsonian translocations tshwm sim hauv ib tus menyuam yug tshiab ntawm ib txhiab. Feem ntau, kev hloov pauv ntawm chromosome 21 tau kuaj pom.
Me me chromosomal translocations kiag li tsis hem tus cab nws tus kheej. Tab sis thaum cov ntsiab lus tseem ceeb ntawm txoj cai raug cuam tshuam, tus me nyuam tseem yuav yug los lossis tuag tom qab ob peb lub hlis, xws li, piv txwv li, tshwm sim nrog Patau syndrome. Tab sis Patau syndrome yog tsawg heev. Kwv yees li 1 ntawm 15,000 yug.
Cov yam tseem ceeb ua rau pom kev hloov pauv hauv chromosomes
Nyob rau hauv qhov xwm txheej, muaj kev hloov pauv hloov pauv, uas yog, tsis tshwm sim los ntawm dab tsi. Tab sis ib puag ncig ua rau nws tus kheej hloov kho rau txoj kev loj hlob ntawm genome. Muaj ntau yam ua rau muaj kev hloov pauv hloov pauv. Cov yam ntxwv no hu ua mutagenic. Cov hauv qab no tau paub:
- cuam tshuam ntawm nitrogenous hauv paus;
- txawv teb chaws DNA biopolymers;
- niam haus thaum cev xeeb tub;
- cuam tshuam tus kab mob thaum cev xeeb tub.
Feem ntau, kev hloov pauv tshwm sim vim muaj kev phom sij ntawm hluav taws xob ntawm lub cev. Muaj feem xyuam rau cov hluav taws xob ultraviolet, proton thiab X-ray hluav taws xob, nrog rau gamma rays.
Chromosomes hloov pauv dab tsi?
Chromosome 13, 14, 15 thiab 21 tau hloov pauv. Qhov kev hloov pauv nrov tshaj plaws thiab txaus ntshai yog Robertsonian hloov pauv ntawm 14 txog 21.chromosomes.
Yog tias meiosis tsim cov chromosome ntxiv (trisomy) hauv tus menyuam hauv plab nrog qhov kev hloov pauv no, tus menyuam yuav yug los nrog Down syndrome. Tib qhov ua ntej tuaj yeem ua tau yog tias Robertsonian hloov chaw tshwm sim ntawm chromosomes 15 thiab 21.
Kev hloov pauv ntawm pawg D chromosomes
Robertsonian kev hloov pauv ntawm pawg D chromosomes cuam tshuam tsuas yog acrocentric chromosomes. Chromosomes 13 thiab 14 koom nrog kev hloov pauv hauv 74% ntawm cov neeg mob thiab lawv raug hu ua kev hloov pauv tsis sib xws, uas feem ntau tsis muaj kev phom sij rau lub neej.
Txawm li cas los xij, muaj ib qho xwm txheej uas tuaj yeem nrog cov kev tsis sib xws. Robertsonian translocation 13, 14 nyob rau hauv cov txiv neej tuaj yeem ua rau lub cev tsis muaj zog ntawm tus txiv neej no (chromosome teeb 45 XY). Vim lub fact tias, vim poob ntawm ob txhais caj npab luv, es tsis txhob ntawm 2 khub ntawm chromosomes, tsuas yog ib tug ntau dua, muaj 2 ntev sawv daws yuav, gametes ntawm xws li ib tug txiv neej yuav tsis muaj peev xwm muab tau cov xeeb ntxwv.
Tib qhov kev hloov pauv Robertsonian ntawm 13, 14 ntawm tus poj niam kuj txo nws lub peev xwm muaj menyuam. Kev coj khaub ncaws muaj nyob rau hauv cov poj niam zoo li no, thiab tseem muaj cov xwm txheej thaum lawv yug me nyuam noj qab nyob zoo. Tab sis kev txheeb cais tseem qhia tau tias cov no tsis tshua muaj tshwm sim. Lawv cov me nyuam feem ntau tsis muaj peev xwm ua tau.
Txoj kev cuam tshuam ntawm kev hloov pauv
Peb twb tau pom tias qee qhov kev hloov pauv ntawm cov qauv zoo li qub thiab tsis ua rau muaj kev hem thawj. Ib qho kev hloov pauv Robertsonian nkaus xwb tsuas yog txiav txim siab los ntawm kev tshuaj xyuas. Tab sis rov translocation rautiam tom ntej ntawm chromosomes twb txaus ntshai lawm.
Robertsonian translocation 15 thiab 21 ua ke nrog lwm yam kev hloov pauv tuaj yeem ua rau tsis txaus siab. Peb yuav piav qhia txog txhua qhov tshwm sim ntawm tus kheej cov qauv kev hloov pauv hauv karyotype kom ntxaws ntxiv. Nco qab tias karyotype yog ib txheej ntawm chromosomes uas muaj nyob hauv ib tus neeg hauv lub nucleus.
Trisomies thiab translocations
Ntxiv rau qhov kev hloov pauv, cov noob caj noob ces paub qhov txawv txav xws li trisomy hauv chromosome. Trisomy txhais tau hais tias tus me nyuam hauv plab karyotype muaj triploid txheej ntawm ib qho ntawm cov chromosomes, es tsis txhob siv 2 daim ntawv luam, mosaic trisomy qee zaum tshwm sim. Ntawd yog, lub teeb triploid tsis pom nyob hauv txhua lub hlwb ntawm lub cev.
Trisomy ua ke nrog Robertsonian translocation ua rau muaj qhov tshwm sim loj heev: xws li Patau syndrome, Edwards syndrome thiab ntau dua Down syndrome. Qee qhov xwm txheej, ib txheej ntawm qhov tsis xws luag ua rau nchuav menyuam ntxov.
Down Syndrome. Kev tshwm sim
Nws yuav tsum tau muab sau tseg tias kev hloov pauv nrog 21 thiab 22 chromosomes ruaj khov dua. Xws li anomalies tsis ua rau tuag, tsis yog ib nrab tuag, tab sis tsuas yog ua rau muaj kev sib txawv hauv kev loj hlob. Yog li, trisomy 21 ua ke nrog Robertsonian kev hloov pauv hauv karyotype hauv kev tshuaj xyuas ntawm karyotype ntawm tus me nyuam hauv plab yog qhov tseeb "kos npe" ntawm Down syndrome, kab mob caj ces.
Down Syndrome yog qhov txawv txav ntawm lub cev thiab lub hlwb. Kev kwv yees ntawm lub neej hauv cov neeg zoo li no yog qhov zoo. Txawm hais tias lub plawv tsis xws luag thiab qee qhov kev hloov pauv ntawm lub cev hauv lub cev pob txha, lawvlub cev ua haujlwm li qub.
Cov cim qhia ntawm tus mob:
- paj ntsej muag;
- nco tus nplaig;
- ntau daim tawv nqaij ntawm caj dab, mus rau hauv quav;
- clinodactyly (curvature of fingers);
- epicanthus;
- kab mob plawv muaj peev xwm ua tau hauv 40% ntawm tus neeg mob.
Cov neeg mob no pib taug kev qeeb dua, hais lus. Thiab nws kuj nyuaj rau lawv kawm ntau dua li lwm cov menyuam yaus hnub nyoog tib yam.
Tseem, lawv muaj peev xwm ua haujlwm tau zoo hauv zej zog, thiab nrog kev txhawb nqa thiab kev ua haujlwm zoo nrog cov menyuam yaus, lawv yuav sib raug zoo rau yav tom ntej.
Patau Syndrome
Tus mob no tsawg dua li Down syndrome, tab sis tus me nyuam no muaj ntau yam tsis xws luag. Yuav luag 80% ntawm cov menyuam uas muaj tus kabmob no tuag hauv 1 xyoos ntawm lub neej.
Xyoo 1960, Klaus Patau tau kawm txog qhov tsis zoo no thiab pom qhov ua rau ntawm caj ces tsis ua haujlwm, txawm hais tias ua ntej nws xyoo 1657 nws tau piav qhia T. Bartolini's syndrome. Kev pheej hmoo ntawm cov kab mob no nce ntxiv rau cov poj niam uas yug menyuam tom qab 31.
Nyob rau hauv cov menyuam yaus no, ntau lub cev tsis xws luag yog ua ke nrog kev puas siab puas ntsws loj hlob. Yam ntxwv ntawm tus mob syndrome:
- Ymicrocephaly;
- tes txawv txav, feem ntau nrog ntiv tes ntxiv;
- pob ntseg tsis sib xws;
- hare lip;
- caj dab luv;
- qhov muag qis;
- obviously "sunken" choj ntawm lub qhov ntswg;
- muag raum thiab lub siab;
- daim di ncauj los yog palate;
- cev xeeb tub tsuas muaj ib lub umbilical artery.
Ib tug me nyuam mos tseem muaj sia nyob tau txais kev kho mob. Thiab lawv muaj peev xwm nyob tau ntev. Tab sis congenital anomalies tseem cuam tshuam qhov xwm ntawm lub neej thiab nws shortness.
Edwards Syndrome
Trisomy ntawm chromosome 18 vim kev hloov pauv ua rau Edwards syndrome. Cov tsos mob no tsis tshua paub zoo. Nrog rau qhov kev kuaj mob no, tus menyuam nyuam qhuav muaj sia nyob mus txog rau lub hlis. Txoj cai ntawm kev xaiv ntuj yuav tsis pub ib tug tsiaj nrog ntau deviations los tsim.
Feem ntau, tus lej sib txawv hauv Edwards syndrome yog kwv yees li 150. Muaj cov hlab ntsha, lub plawv, thiab lub cev tsis zoo. Cerebellar hypoplasia yeej ib txwm muaj nyob rau hauv cov me nyuam mos. Anomalies nyob rau hauv cov qauv ntawm cov ntiv tes yog ua tau. Heev feem ntau, xws li ib tug txawv anomaly li deformity ntawm ko taw tshwm.
Kev kuaj dab tsi pom qhov txawv txav thaum lub sij hawm kev loj hlob ntawm fetal?
txhawm rau txheeb xyuas tus menyuam hauv plab karyotype, nws yog qhov yuav tsum tau txais cov khoom siv - fetal cells.
Muaj ntau qhov kev xeem. Cia peb saib seb nws tshwm sim li cas.
1. Biopsy ntawm chorionic villi. Kev tshuaj xyuas yog nqa tawm thaum lub lim tiam 10. Cov villi no yog ib feem ntawm cov placenta. Cov khoom siv lom neeg no yuav qhia txhua yam txog lub neej yav tom ntej fetus.
2. Amniocentesis. Nrog kev pab los ntawm ib rab koob, ntau lub fetus hlwb thiab cov kua amniotic raug coj mus. Lawv tau noj ntau zaus thaum lub asthiv thib 16 ntawm cev xeeb tub, thiab tom qab ob peb lub lis piam, nkawm niam txiv tuaj yeem tau txais cov ncauj lus kom ntxawscov ntaub ntawv qhia txog nyiaj pab menyuam yaus.
Cov niam txiv uas muaj kev pheej hmoo ntau ntxiv rau kev yug menyuam uas muaj qhov txawv txav raug xa mus rau qhov kev tshuaj ntsuam no. Feem ntau, cov khub niam txiv uas muaj:
1) tau nchuav menyuam tsis tau piav qhia;
2) nkawm niam txiv tsis tuaj yeem xeeb tau ntev;
3) muaj kev sib raug zoo nyob rau hauv lub genus.
Cov tub ntxhais hluas zoo li no yuav muaj Robertsonian kev hloov pauv ntawm qee cov chromosome. Thiab yog li ntawd, lawv yuav tsum ua ib qho kev ntsuam xyuas ntawm lawv cov karyotype ua ntej txhawm rau paub tias yuav ua li cas thiaj li muaj feem muaj sia nyob thiab yug me nyuam noj qab haus huv.
