Ukuqonda ukuchithwa kwiiSalathisi
Ukuba ufunde ngesimo somfuzo, usenokufumana amagama athi "homozygous" okanye "heterozygous"? Kodwa yintoni le nto ithetha ntoni? Yaye zeziphi iziphumo ezibonakalayo zokuba "u-homozygous" okanye "heterozygous" kwizinto ezithile?
Yintoni iGene ?
Ngaphambi kokuchaza i-homozygous kunye ne-heterozygous, kufuneka sicinge ngokuphathelele izakhi zofuzo. Inye nganye yeeseli zakho iqulethe ixesha elide kakhulu leDNA (deoxyribonucleic acid).
Le nto yinto efanelekileyo yokufumana kuwo ngamnye kubazali bakho.
I-DNA iqulethwe uchungechunge lwezinto ezithile ezibizwa ngokuba yi-nucleotides. Kukho iintlobo ezine ezahlukeneyo ze-nucleotides kwi-DNA: i-adenine (A), i-guanine (G), i-cytosine (C) kunye ne-thymine (T). Ngaphakathi kweseli, i-DNA isoloko ifunyenwe kwi-chromosomes (ifunyenwe kwiindidi ezi-23 ezahlukeneyo).
AmaGenesis azinxalenye ezithile zeDNA ngenjongo ecacileyo. Ezi ziqendu zisetyenziswe ngenye imishini ngaphakathi kweseli ukwenza iiprotheni ezithile. Iiprotheni zakhiwo zezakhiwo ezisetyenziselwa iindima ezibalulekileyo ngaphakathi komzimba, kubandakanywa inkxaso yenkxaso, ukutyunjwa kweeseli, ukulungiswa kwamachiza, kunye nokuthutha. Iseli yenza iprotheni (ngaphandle kweebhloko zayo zokwakha, i-amino acid) ngokufunda ulandelelwano lwee-nucleotide ezifumaneka kwi-DNA. Iseli isebenzisa uhlobo lwenkqubo yokuguqulela ukusebenzisa ulwazi kwi-DNA ukwakha amaprotheni athile kunye nezakhiwo kunye nemisebenzi ethile.
Iizakhi ezikhethekileyo emzimbeni zizalise indima ehlukileyo. Ngokomzekelo, i-hemoglobin iyinxalenye yeprotheni eyinkimbinkimbi eyenza ukuqhuba i-oksijini egazini. Izakhi zofuzo ezahlukeneyo (ezifunyenwe kwi-DNA) zisetyenziselwa iseli ukwenza iifomethi ezithile ezifunekayo kule njongo.
Uzuza i-DNA yabazali bakho.
Ukuthetha ngokubanzi, isiqingatha seDNA yakho sivela kumama wakho, kunye nesiqingatha sisuka koyihlo. Kwizinto ezininzi zegesi, uzuza ikopi enye kumama wakho kunye noyihlo. (Nangona kunjalo, kukho umcimbi obandakanya i-chromosomes ekhethekileyo ebizwa ngokuba ngama-chromosomes ngokwesini. Ngenxa yendlela indlela i-chromosomes yesini isebenza ngayo, abesilisa bafumana ilifa linye yeezityalo ezithile.)
Utshintsho kwiGenesis
I-code of genetic of human beings is similar: I-99% yeenucleotides eziyingxenye yegesi zifana nabantu bonke. Nangona kunjalo, kukho ukuhlukahluka kwindlela yokulandelelana kwama-nucleotides kwiijethi ezithile. Ngokomzekelo, ukuhlukahluka kwesinye somfuzo kunokuqala ngokulandelelana I-TGG, kwaye enye inguqu ingaqalisa i- C ye- TGCT esikhundleni. Ukuhlukahluka kohlobo lweejeni kuthiwa yi-alleles.
Ngamanye amaxesha ukuhlukahluka okwenziwe kungenzi umehluko kwiprotheni ekupheleni, kodwa ngamanye amaxesha bayakwenza. Zingabangela ulwahlulo oluncinci kwiprotheni eyenza lusebenze ngokuthe ngqo.
Umntu kuthiwa u-homozygous for gene if they have two copies of gene. Ngokomzekelo wethu, oku kuya kuba yiikopi ezimbini zenguqu ye-gene "I-TGCT" okanye iikopi ezimbini zenguqu eqala "I-TGCT ye- C ." I-Heterozygous ithetha nje ukuba umntu uneenguqu ezimbini ezahlukeneyo zesini ukusuka kumzali omnye, kunye nomnye kumnye umzali).
Ngokomzekelo wethu, i-heterozygote iya kuba neyodwa inguqu ye-gene iqala "I-TGCT" kunye nenye enye inguqu ye-gene "I-TGCT".
Izifo
Uninzi lwezi zinguqu alunanto enkulu, kwaye nje lufaka isandla kwiimeko eziqhelekileyo zomntu. Nangona kunjalo, ezinye izitshintsho ezithile zingakhokelela kwizifo zabantu. Oko ngokuqhelekileyo abantu abakuthethayo xa bethetha "homozygous" kunye ne "heterozygous": uhlobo oluthile lokuguquka okubangelwa izifo.
Omnye umzekelo i- anemia yesalente yesigane . Kwi-cell anemia yesigane, kukho utshintsho kwi-nucleotide enye eyenza utshintsho kwi-nucleotide ye-gene (ebizwa ngokuba yi-β-globin gene).
Oku kubangela ukuba utshintsho olubalulekileyo kwi-hemoglobin. Ngenxa yoko, iiseli ezibomvu zegazi ezithwala i-hemoglobin ziqala ukuphuka ngaphambi kwexesha. Oku kunokukhokelela kwiingxaki ezinjenge-anemia nokuphefumula.
Ngokuqhelekileyo, kukho iindlela ezintathu ezahlukeneyo:
- Omnye u-homozygous kwi-gene ye-β-globin gene (iikopi eziqhelekileyo)
- Omnye u-heterozygous (unomfanekiso oqhelekileyo kunye nekopi engavumelekanga)
- Omnye u-homozygous kwi-gene ye-β-globin gene (iikopi ezimbini ezingavumelekanga)
Abantu abahlala kwi-heterozygous kwi-genele yegeni yesigane banekhophi enye ye-gene (ukusuka komzali omnye) kunye nekopi enye echaphazelekayo yemfuza (ukusuka komnye umzali). Aba bantu abafumani iimpawu zesifo se-anemia yesalente. Nangona kunjalo, abantu abane-homozygous kwi-gene ye-β-globin gene bafumana iimpawu ze-anemia ye-sickle cell.
Ngaba i-Heterozygotes Ngaba i-Genetic Diseases?
Ewe, kodwa akunjalo. Kuxhomekeke kuhlobo lwesifo. Kwezinye iintlobo zezifo ze- genetic , umntu ohamba nge-heterozygous cishe uya kufumana isifo.
Kwizifo ezibangelwa yizinto ezibizwa ngokuba yizilwanyana eziphezulu, umntu ufuna kuphela ikopi enye engafanelekanga yemfuza ukuba abe neengxaki. Omnye umzekelo yintlungu yesifo se- Huntington . Umntu onomdla owodwa ochaphazelekayo (ozuzwa kumzali okanye ngamnye) uya kufumana ngokuqinisekileyo eso sifo njenge-heterozygote. (I-homozygote efumana iikopi ezimbini ezingavamile zesi sifo kubazali bobabini ziya kuthinteka, kodwa oku akuqhelekanga kwizifo eziphezulu zesifo.)
Nangona kunjalo, ngenxa yezifo eziguqulwayo, njenge-anemia ye-sickle cell, i-heterozygotes ayifumani isifo. (Nangona kunjalo, ngamanye amaxesha banokuba nezinye iinguqu ezifihlakeleyo, kuxhomekeke kwisifo.)
Kuthiwani Ngama-Chromosomes eSondo?
I-chromosomes yesini i-X ne-Y i-chromosomes edlala indima ekuhlukisweni kwesini. Abasetyhini bazuza iili-chromosomes ze-X, omnye kumzali ngamnye. Ngoko isetyhini inokuthi ithathwa njenge-homozygous okanye i-heterozygous malunga nomxholo othile kwi-X chromosome.
Amadoda adibanisa ngakumbi. Bazuza ii-chromosomes zesini ezahlukeneyo: X kunye no-Y. Ngenxa yokuba ezi zi-chromosomes ezimbini zihlukile, amagama athi "homozygous" nelithi "heterozygous" ayisebenzisi kula ma-chromosomes amabini kumadoda. Usenokuba weva ngezifo ezixhatshazwa ngesondo, njengeDuchenne muscular dystrophy . Ezi zibonisa uhlobo lwefa elihlukile kunezifo eziqhelekileyo okanye eziphambili ezizuzwa ngezinye i-chromosomes (ezibizwa ngokuba ngama-autosomes).
Heterozygote Inzuzo
Kwezinye izifo zengqondo, kungenzeka ukuba i-heterozygote inika umntu inzuzo ethile. Ngokomzekelo, kucatshangelwa ukuba i-heterozygote yesigulo se-anemia yesigenjana segulane sinokukhusela i-malaria, ngokuthelekisa kubantu abangenayo ikopi engavumelekanga.
Ifa
Makhe sicinge ngeenguqu ezimbini ze-gene: A ne-a. Xa abantu ababini banomntwana, kukho amathuba amaninzi:
- Bobabini abazali ba-AA. Bonke abantwana babo baya kuba yi-AA kunye (i-homozygous for AA).
- Bobabini abazali ba. Emva koko bonke abantwana babo baya kuba kunye (homozygous for aa).
- Umzali omnye ngu-Aa nomnye umzali ngu-Aa. Umntwana wabo uneepesenti ezingama-25 yokuba yi-AA (homozygous), ama-50 ekhulwini amathuba okuba abe-Aa (heterozygous), kunye nama-25 ekhulwini amathuba okuba (homozygous)
- Omnye umzali ngu-Aa kunye nomnye u-aa. Umntwana wabo unamava engama-50 e-Aa (heterozygous) kunye nama-50 ekhulwini amathuba okuba (homozygous).
- Omnye umzali ngu-Aa kwaye enye i-AA. Umntwana unekhefu lama-50 e-AA (homozygous) kunye nama-50 ekhulwini ithuba lokuba yi-Aa (heterozygous).
ILizwi
Ukufunda i-genetics kuyinkimbinkimbi. Ukuba imeko yezofuzo isebenza kwintsapho yakho, unganqikazi ukubonisana neengcali zakho zempilo malunga noko oku kuthetha ntoni kuwe.
> Imithombo:
> Berg JM, uTymoczko JL, uStryer L. Biochemistry. 6 th . ENew York, NY: WH Feedman kunye neNkampani; 2007.
> Frenette PS, Atweh GF. Isifo sesisifo sesifo: iziphumo zakudala, iingcinga ezintsha kunye nesithembiso esizayo. Umbhalo woPhando lweZliniki . 2007; 117 (4): 850-858. i-doi: 10.1172 / JCI30920.
> Nussbaum RL, McInnes RR, uWillard HF, uHamosh A. Genetics kwiMithi ye-7. Philadelphia, PA: Sauders Elsevier; 2007.