Halittar jini

Kwayar halitta ita ce nazarin gado, hanyar da iyaye ke bi ta hanyar isar da wasu kwayoyin ga 'ya'yansu. Bayyanar mutum - tsayi, launin gashi, launin fata, da launin ido - ƙaddara ce ke tabbatar da ita. Sauran halayen da gado ya shafa sune:

• Yiwuwar kamuwa da wasu cututtuka
• Hankali na hankali
• Baiwa ta halitta

Hali mara kyau (ɓacin rai) wanda ya ratsa ta cikin dangi (wanda aka gada) na iya:

• Ba ku da wani tasiri a kan lafiyar ku ko lafiyar ku. Misali, yanayin zai iya haifar da farin faci na gashi ko kunnen kunne wanda ya fi tsayi fiye da yadda aka saba.
• Yi sakamako kaɗan kawai, kamar makantar launi.
• Yi babban tasiri akan ƙimar ka ko tsawon rayuwar ka.

Don yawancin rikice-rikicen kwayoyin, ana ba da shawara game da kwayoyin halitta. Hakanan ma'aurata da yawa na iya neman neman haihuwa idan ɗayansu yana da cutar ƙwayar cuta.

Humanan Adam suna da ƙwayoyin halitta tare da chromosomes 46. Wadannan sun kunshi chromosomes 2 wadanda ke tantance irin jinsin da suke (X da Y chromosomes), da kuma nau'i-nau'i 22 wadanda basuda jima'i (autosomal) chromosomes. Maza sune "46, XY" kuma mata sune "46, XX." Kwayoyin chromosomes sun kunshi sassan bayanan kwayoyin halitta masu suna DNA. Kowane chromosome ya ƙunshi sassan DNA da ake kira genes. Kwayoyin halitta suna dauke da bayanan da jikinka yake bukata don yin wasu sunadarai.

Kowane chromosomes na autosomal ya hada da chromosome daya daga mahaifiya daya kuma daga mahaifinsa. Kowane chromosome a cikin ma'aurata yana ɗauke da bayanai iri ɗaya. ma’ana, kowane nau’in chromosome yana da kwayoyin halitta iri daya. Wani lokaci akan sami ‘yan bambancin wadannan kwayoyin halittar. Wadannan bambance-bambancen suna faruwa kasa da 1% na jerin DNA. Kwayoyin halittar da ke da waɗannan bambancin ana kiransu allele.

Wasu daga cikin waɗannan bambancin na iya haifar da kwayar halitta wacce ba al'ada ba. Wata kwayar halitta wacce ba ta dace ba na iya haifar da furotin mara ƙima ko ƙarancin adadin furotin na al'ada. A cikin kwayoyin chromosomes guda biyu, akwai kwafi biyu na kowane kwayar halitta, daya daga kowane mahaifa. Idan ɗayan waɗannan ƙwayoyin cuta ba su da matsala, ɗayan na iya yin isasshen furotin don kada wata cuta ta taso. Lokacin da wannan ya faru, akan kira kwayar halittar da ba ta dace ba. An ce kwayoyin gadoji suna da gado a cikin ko dai wani tasirin motsa jiki ko tsarin haɗin X. Idan kwafi biyu na kwayoyin da ba na al'ada ba suna nan, cuta na iya bunkasa.

Koyaya, idan ana buƙatar kwayar halitta guda ɗaya da ba ta dace ba don samar da cuta, yana haifar da wata cuta ta gado mai rinjaye. Game da cuta mai yawan gaske, idan kwayar cuta guda daya ta gado daga uwa ko uba, da alama yaron zai nuna cutar.

Mutumin da ke da kwayar halittar mahaifa guda daya ana kiran shi heterozygous saboda wannan kwayar halittar. Idan yaro ya karɓi kwayar cutar ta mahaifa daga iyayensa biyu, yaron zai nuna cutar kuma zai zama mai kama da ɗabi'a (ko heterozygous) don wannan kwayar.

RASHIN JINI

Kusan dukkan cututtuka suna da tsarin halittar su. Koyaya, mahimmancin wannan ɓangaren ya bambanta. Rikicin da kwayoyin halitta ke taka muhimmiyar rawa (cututtukan kwayoyin halitta) ana iya rarraba su azaman:

• Laifi-kwayar halitta
• Cutar chromosomal
• Abubuwan da yawa

Ciwon kwayar halitta guda (wanda kuma ake kira rikicewar Mendelian) yana faruwa ne tawaya a cikin wani jinsi na musamman. Raunin larura guda ɗaya ba safai ba. Amma tunda akwai dubunnan sanannun rikice-rikicen kwayar halitta guda daya, tasirin tasirinsu yana da mahimmanci.

Ana haifar da rikice-rikicen kwayoyin guda daya ta yadda ake yada su cikin dangi. Akwai hanyoyi 6 na asali na gado daya:

• Autosomal rinjaye
• Autosomal koma baya
• X-nasaba rinjaye
• X-nasaba recessive
• Rabon gado
• Gadon mahaifiya (mitochondrial)

Sakamakon lura da kwayar halitta (bayyanar cuta) ana kiranta da suna

A cikin gadon mallaka mafi girma, rashin daidaito ko rashin daidaituwa yawanci yakan bayyana a kowane ƙarni. Duk lokacin da mahaifa da cutar ta shafa, walau mata ko maza, suna da ɗa, wannan yaron yana da damar kashi 50% na gadon cutar.

Ana kiran mutanen da ke da kwafin kwaya daya na kwayar cutar mai yaduwa. Masu dauke da cutar galibi ba su da alamun cutar. Amma, ana iya samun kwayar halittar galibi ta hanyar gwaje-gwajen gwaji masu mahimmanci.

A cikin rabon gado na gado, iyayen wanda abin ya shafa ba za su iya nuna cutar ba (masu ɗauka ne). A matsakaici, damar da iyaye masu ɗauka ke iya samun yara waɗanda suka kamu da cutar shine 25% tare da kowane ciki. Yaran yara maza da mata daidai ake iya kamuwa da su. Don yaro ya sami alamun rashin lafiya na rashin lafiyar jiki, dole ne yaro ya sami asalin mahaifa daga iyayen biyu. Saboda yawancin rikice-rikicen recessive ba safai ba, yaro yana cikin haɗarin kamuwa da cuta idan iyayensa suna da dangantaka. Mutanen da suke da alaƙa da alama sun gaji gado iri ɗaya daga magabatan gama gari.

A cikin rabon gado mai nasaba da X, damar kamuwa da cutar ta fi maza girma fiye da mata. Tunda kwayar halittar da ba ta dace ba ke ɗauke da kwayar cutar ta X (mace), mazan ba sa aika shi ga ɗiyansu maza (waɗanda za su karɓi kwayar Y daga mahaifinsu). Koyaya, suna watsa shi ga 'ya'yansu mata. A cikin mata, kasancewar kwayar chromosome daya na al'ada yana rufe tasirin X chromosome tare da kwayar halittar da ba ta dace ba. Don haka, kusan dukkanin daughtersa daughtersan ana ofan mutumin da abin ya shafa sun zama na al'ada, amma dukansu masu ɗaukar jigilar mahaifa ne. Duk lokacin da waɗannan 'ya'ya mata suka haifi ɗa, akwai damar kashi 50% ɗana ya karɓi kwayar halittar da ba ta dace ba.

A cikin babban gado mai nasaba da X, kwayar halittar da ba ta dace ba tana bayyana ne a cikin mata koda kuwa akwai yanayin ch chromosome na yau da kullun. Tunda maza sunada Y chromosome ga yayansu, mazan da abin ya shafa ba zai shafi 'ya'yansu ba. Duk 'ya'yansu mata zai shafa, duk da haka. 'Ya'ya maza ko mata mata masu fama da cutar za su sami damar kamuwa da cutar kashi 50%.

MISALOLI NA GUDA-ZUFE GUDA

Autosomal ya dawo:

• Rashin ADA (wani lokacin ana kiransa "yaro a cikin kumfa" cuta)
• Rashin Alpha-1-antitrypsin (AAT)
• Cystic fibrosis (CF)
• Yankuniya (PKU)
• Cutar Sikila

X-nasaba recessive:

• Duchenne dystrophy na muscular
• Hemophilia A

Autosomal rinjaye:

• Ciwan hypercholesterolemia
• Ciwon Marfan

X-nasaba rinjaye:

Aan kaɗan, kaɗan ne, cuta, ke da nasaba da haɗin X. Ofaya daga cikin waɗannan shine rickets hypophosphatemic, wanda ake kira bitamin D - ƙyamar rickets.

LALACEWAR KIRSIMA

A cikin rikice-rikice na chromosomal, aibin yana faruwa ne saboda ko dai ƙari ko rashin ƙwayoyin halittar da ke ƙunshe cikin duka ƙarancin chromosome ko chromosome.

Cutar chromosomal sun haɗa da:

• 22q11.2 cututtukan microdeletion
• Rashin ciwo
• Ciwon Klinefelter
• Ciwon Turner

MAGANGANUN YADDA AKEYI

Yawancin cututtukan da aka fi sani suna faruwa ne ta hanyar hulɗar kwayoyin halitta da dama a cikin mahalli (alal misali, cututtuka a cikin uwa da magunguna). Wadannan sun hada da:

• Asthma
• Ciwon daji
• Ciwon zuciya
• Ciwon suga
• Hawan jini
• Buguwa

MITOCHONDRIAL RASHIN RIKICIN DNA

Mitochondria ƙananan sifofi ne waɗanda aka samo a cikin yawancin ƙwayoyin jiki. Su ke da alhakin samar da makamashi a cikin sel. Mitochondria ya ƙunshi nasu DNA na sirri.

A cikin 'yan shekarun nan, yawancin rikice-rikice sun nuna sakamakon sakamakon canje-canje (maye gurbi) a cikin mitochondrial DNA. Saboda mitochondria ya fito ne kawai daga kwan mace, yawancin cututtukan da suka shafi DNA suna wucewa daga uwa.

Cutar da ke da alaƙa da DNA na Mitochondrial na iya bayyana a kowane zamani. Suna da alamomi iri-iri da alamu. Wadannan rikice-rikice na iya haifar da:

• Makaho
• Ci gaban bata lokaci
• Matsalar ciki
• Rashin ji
• Matsalar bugun zuciya
• Rikici na rayuwa
• Girman jiki

Wasu wasu rikice-rikice kuma ana kiran su da cuta ta mitochondrial, amma ba su haɗa da maye gurbi a cikin mitochondrial DNA. Wadannan rikice-rikicen galibi galibi lahani ne na zuriya. Suna bin tsarin gado kamar sauran cututtukan kwayar halitta guda. Mafi yawansu ba su da matsala.

Homozygous; Gado; Tsakar gida; Hanyoyin gado; Gado da cuta; Mai mutuntawa; Alamar kwayar halitta

• Halittar jini

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Korf BR. Ka'idojin gado. A cikin: Goldman L, Schafer AI, eds. Magungunan Goldman-Cecil. 26th ed. Philadelphia, PA: Elsevier; 2020: babi na 35.

Scott DA, Lee B. Tsarin kwayar halitta a likitan yara. A cikin: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Littafin koyar da ilimin yara. 21st ed. Philadelphia, PA: Elsevier; 2020: babi na 95.