Abubuwan da ke da alaƙa da jima'i

Cututtukan da ke da alaƙa da jima'i suna yaduwa ta wurin dangi ta ɗayan chromosomes na X ko Y. X da Y sune chromosomes na jima'i.

Babban gado yana faruwa yayin da kwayar halittar mahaifa daga mahaifa ɗaya ta haifar da cuta, duk da cewa kwayar halittar ɗayan mahaifa ta al'ada ce. Kwayar halittar da ba ta dace ba ta mamaye.

Amma a cikin rabon gado, dukkan kwayoyin halittun da suka dace dole ne su zama sababbai don haifar da cuta. Idan kwayar halitta daya kawai a cikin biyun ba ta al'ada ba, cutar ba ta faruwa ko ta kasance mai sauƙi. Wani wanda yake da kwayar halitta guda daya mara kyau (amma babu alamun bayyanar) ana kiranta mai ɗauka. Masu dauke da cutar na iya daukar kwayar halittar da ba ta dace ba ga 'ya'yansu.

Kalmar "mai nasaba da jima'i" mafi yawan lokuta tana nufin recessive mai nasaba da X.

Cututtukan da ke da nasaba da alakar X ba galibi suna faruwa ne ga maza. Maza suna da chromosome X guda ɗaya tak. Wata kwayar halitta mai matukar tasiri akan wannan chromosome din zai haifar da cutar.

Y chromosome shine sauran rabin nau'ikan halittar XY a jikin namiji. Duk da haka, Y chromosome ba ya ƙunsar yawancin kwayoyin halittar X chromosome. Saboda wannan, ba ya kare namiji. Cututtuka kamar su hemophilia da Duchenne dystrophy na faruwa ne daga kwayar halittar da ke kan kwayar cutar ta X chromosome.

BAYANAI NA GASKIYA

A kowane ciki, idan mahaifiya dauke da wata cuta (tana da ch chromosome daya mara kyau X) kuma mahaifin ba mai dauke da cutar bane, sakamakon da ake tsammani shine:

• 25% dama na ɗa namiji lafiyayye
• 25% damar yaro tare da cuta
• 25% damar yarinya mai lafiya
• 25% dama na ɗauke da yarinya ba tare da cuta ba

Idan uba yana da cutar kuma mahaifiyarsa ba mai ɗauke bane, sakamakon da ake tsammanin shine:

• 50% damar samun ɗa namiji lafiyayye
• 50% damar samun yarinya ba tare da cutar wacce ke dauke da ita ba

Wannan yana nufin cewa babu ɗa daga cikin yaransa da zai nuna alamun cutar a zahiri, amma za a iya ba da halayen ga jikokinsa.

X-LINKED RASHIN CUTUTTUKA A CIKIN MATA

Mata na iya samun cuta mai nasaba da alaƙar X, amma wannan ba safai ba. Za'a buƙaci jinsi mara kyau akan X chromosome daga kowane mahaifa, tunda mace tana da chromosomes guda biyu. Wannan na iya faruwa a cikin yanayi guda biyu da ke ƙasa.

A kowane ciki, idan mahaifiya ta kasance mai ɗauka kuma uba yana da cutar, sakamakon da ake tsammani shine:

• 25% dama na ɗa namiji lafiyayye
• 25% damar yaro tare da cutar
• 25% damar yarinyar dako
• 25% dama na yarinya mai cutar

Idan uwa da uba suna da cutar, sakamakon da ake tsammani shine:

• 100% dama na yaron yana da cutar, ko yaro ko yarinya

Rashin daidaito na ɗayan waɗannan al'amuran guda biyu yayi ƙasa sosai cewa wasu cututtukan da ke da alaƙa da cutar X wani lokaci ana kiran su da cutar maza kawai. Koyaya, wannan ba daidai bane ta hanyar fasaha.

Mata masu ɗauka na iya samun chromosome na al'ada na X wanda ba shi da aiki yadda ya kamata. Wannan ana kiransa "karkataccen X-inactivation." Wadannan mata na iya samun alamomi irin na maza, ko kuma suna da larurar alamura kawai.

Gado - mai alaƙa da jima'i; Genetics - haɗuwa da jima'i; X-nasaba recessive

• Halittar jini

Feero WG, Zazove P, Chen F. Clinical genomics. A cikin: Rakel RE, Rakel DP, eds. Littafin karatun Magungunan Iyali. 9th ed. Philadelphia, PA: Elsevier Saunders; 2016: babi na 43.

Gregg AR, Kuller JA. Tsarin halittar mutum da tsarin gado. A cikin: Resnik R, Lockwood CJ, Moore TR, Greene MF, Copel JA, Silver RM, eds. Creasy da Resnik na Maganin Uwar-Gida: Ka'idoji da Ayyuka. 8th ed. Philadelphia, PA: Elsevier; 2019: babi na 1.

Jorde LB, Carey JC, Bamshad MJ. Hanyoyin gado da alaƙa da jima'i. A cikin: Jorde LB, Carey JC, Bamshad MJ, eds. Kwayar Halitta. Na 6 ed. Philadelphia, PA: Elsevier; 2020: babi na 5.

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