Nazarin Tagwaye da "Al'adun Gina Jiki"

"Abin da ya yi kama da rafi mai kama da juna na tagwaye maza takwas masu shekaru takwas suna kwarara zuwa cikin dakin. Tagwaye bayan tagwaye ... fuskokinsu, fuskokinsu na maimaita don akwai guda ɗaya kawai tsakanin su da yawa ... (shafi. 172) "... kamar tsutsotsi da suka tarwatse ..." (shafi na 178) ya rubuta Aldous Huxley a Jarumar Sabuwar Duniya . (1932) Anan shine "ƙa'idar samar da taro a ƙarshe ana amfani da ilimin halitta:" (p.9) kirkirar miliyoyin tagwaye masu kama, (kuma "ba yin biyun biyun da uku ba kamar yadda a cikin tsoffin ranakun viviparous") (shafi na 8) amma "babban ci gaba akan yanayi" (shafi na 8) wanda aka yi niyyar ƙirƙirar zaman lafiyar jama'a.

Hotunan Jarumar Sabuwar Duniya suna tsoratarwa kuma suna korewa, amma tagwaye sun burge mutane cikin tarihi. Akwai tagwayen tagwayen tarihin Roman, Romulus da Remus, waɗanda kyarkeci ya shayar da su, kuma wanda Romulus ya ci gaba da samun tsohuwar Rome. Kuma akwai brothersan'uwan juna tagwaye Yakubu da Isuwa a cikin Littafin Farawa: Isuwa, "na farko ya fito duk ja, duk kamar rigar gashi." (Farawa 25: 25) "Ga ɗan'uwana Isuwa mutum ne mai gashi, ni kuma mutum ne mai santsi." (Farawa 27:11) Dauki Pew, by Alan Bennett, daga Bayan Fringe: https://www.youtube.com/watch?v=UOsYN---eGk.) Kuma a cikin Shakespeare Dare Na Sha Biyu , tagwaye Viola da Sebastian suna kama da juna sosai, an kwatanta su da "fuska ɗaya, murya ɗaya, al'ada ɗaya da mutum biyu. Halin yanayi, wato, kuma ba haka bane," in ji Duke. Kuma Antonio ya ƙara da cewa, "Ta yaya kuka raba kanku? Tsutsar tuffa a cikin biyu ba ta fi tagwayen waɗannan halittu biyu ba." (Dokar V, Scene 1)

Kodayake Viola da Sebastian sun kasance masu wuyar rarrabewa da juna, sun kasance, kamar maza da mata, 'yan uwan ​​juna, ko dizygotic (DZ) tagwaye kuma suna tasowa a cikin utero daga hadi ɗaya na ƙwai biyu ta maniyyi biyu. Suna rabawa, kamar sauran 'yan uwan ​​juna a cikin iyali, kashi 50% ne kawai na DNA ɗin su. Tagwaye masu kama da juna (monozygotic (MZ) suna tasowa daga rarrabuwar amfrayo guda ɗaya kuma suna raba kashi 100% na DNA ɗin su don haka koyaushe suna jinsi ɗaya. Ƙudurin bincike don tabbatar da zygosity shine matakin farko na kimanta tagwaye kuma galibi ana yin shi ta hanyar bincika launin gashi, idanu, sifar kunnuwa, baki, hakora, da sauran halaye na zahiri, gami da yatsan yatsa, da kuma ta hanyar nazarin rukunin antigen na jini. . (Börjeson, da Acta Paediatrica Scandinavica , 1976)

Shawarar amfani da tagwaye a bincike galibi ana danganta ta ga Sir Francis Galton, dan uwan ​​Charles Darwin, a ƙarshen karni na 19. Galton ya buga littattafai guda biyu, gami da Tarihin Tagwaye kuma yana da sha'awar rarrabewa "tsakanin tasirin ɗabi'un da aka samu a lokacin haihuwa da waɗanda ke haifar da yanayi na musamman na rayuwa," watau, tsakanin yanayi da haɓaka. (kamar yadda aka nakalto a Gedda, Tagwaye a Tarihi da Kimiyya , 1961, shafi na 24-25) Galton, duk da haka, bai kwatanta tagwayen 'yan uwan ​​juna da na juna ba don haka "ba za a iya ɗaukar shi mai ƙirƙira hanyar tagwayen ba." (Teo da Ball, Tarihin Kimiyyar Dan Adam , 2009)

Sauran masu binciken sun biyo baya amma akwai duhu game da tagwayen bincike a farkon da tsakiyar shekarun karni na 20, kamar yadda aka tabbatar a cikin aikin von Verschuer, wanda shine mashawarcin Josef Mengele, sananne ga karatun tagwayensa a Auschwitz lokacin Duniya Yaki na Biyu. A bayyane yake von Verschuer, wanda masanin kimiyya ne da ake girmamawa, ya kasance ɗan Nazi da mugun ƙiyayya wanda ya yi amfani da tagwayen karatunsa don ciyar da siyasar wariyar launin fata gaba. (Müller-Hill, Tarihi da Falsafa na Kimiyyar Rayuwa , 1999) An ba da rahoton, Mengele ya aiko da samfuran idanu da samfuran jini daga tagwayen 200 wanda ya gudanar da binciken ɗan adam da ba daidai ba, zuwa von Verschuer don bincike. Kashi 10% na waɗannan tagwayen ne kawai suka tsira daga gwajin ɗan adam na Mengele. (Müller-Hill, 1999) Don tattaunawa game da ɓatancin kimiyya ta von Verschuer da Mengele da mahimmancin ƙuduri don “sanya fifikon majiyyaci sama da na likitan,” duba Coller, Jaridar Binciken Clinical , 2006, wanda ya nanata cewa akwai “manyan ƙima na ilimin ɗan adam na likitanci: ƙima ko tsarkin rayuwar kowane ɗan adam; girmama mutuncin ɗan adam, bikin bambancin ɗan adam, da nuna jin ƙai game da sarkakiyar yanayin ɗan adam.” (Coller, 2006) Kuma don tattaunawa kan abubuwan da aka yi watsi da su da "tarihin bita" na binciken tagwaye da aka samu a wasu litattafan karatu, duba Teo da Ball, 2009.

Masu binciken farkon karni na 20, gami da von Verschuer, duk da haka, sun fara la’akari da rawar da kwayoyin halittu ke takawa musamman a fannin kiba. Dr. George A. Bray, a cikin littafinsa na ilimi, Yakin Tashin Hankali (2007), ya bincika tarihin binciken kiba da sake buga takardu na asali ta Davenport (shafi na 474 ff) (1923), da kuma ta von Verschuer (shafi na 492 ff) (1927.) Davenport, wanda ya yi amfani da rabon mu sani a matsayin ma'aunin ma'aunin jiki (BMI), shine farkon wanda yayi nazarin alaƙar jinsin halittu da muhalli a cikin kiba kuma ya tambaya, "Yaya nisan wannan bambancin ke tsakanin tsakanin sirirrai da masu jiki ya dogara da abubuwan tsarin mulki?" (shafi na 474) Daga Dr. Bray ne (wanda ya ari daga wurin mai ba da shawara Edwin B. Astwood) (shafi na 148) na ɗauki taken na. Gadon Gwargwado .

Manyan karatuttukan tagwaye sun biyo baya, gami da mai binciken Sweden Börjeson (1976), wanda yayi nazarin mahimmancin gado da muhalli ta hanyar kwatanta bambance-bambancen da ke tsakanin MZ da tagwayen DZ, da hotunan tagwayen da ke bayyana a nan. Bugu da ƙari, mai bincike na Kanada Claude Bouchard da abokan aiki sun ƙirƙira abin da ake kira dogon nazari "Quebec Overfeeding Study," inda suka yi nazarin nau'i-nau'i guda 12 na ma'aunin ma'aunin tagwaye maza na yau da kullun waɗanda suka kasance ƙarƙashin yanayin sarrafawa na tsawon kwanaki 120 a cikin ɗakin marasa lafiya kuma aka basu abinci. Ƙarin adadin kuzari 1000 kowace rana don kwanaki shida a mako don 84 daga cikin kwanakin. (Bouchard et al, Jaridar New England Journal of Medicine , 1990; Redden da Allison, Sharhin Kiba , 2004; Bouchard, Jaridar American Nutrition Clinical , 2009; Bouchard et al, Jaridar Kiba ta Duniya , 2014; ) Matsakaicin ƙimar nauyi shine kg 8.1 amma ya kasance daga 4.3 zuwa 13.3 kg. Abin ban mamaki, yawan cin abinci ya haifar da mahimmancin nauyin jikin mutum da yawan ribar mai a cikin kowane tagwayen MZ, amma akwai sau uku mafi bambanci tsakanin nau'i -nau'i daban -daban fiye da na ma'aurata. A takaice dai, tsayayyen iko na adadin adadin yawan cin abinci da iyakancewar motsa jiki ya haifar da martani daban -daban dangane da yawan jiki, ƙirar jiki, har ma da rarraba kitse na yanki a cikin tagwaye daban -daban. Bouchard ya nanata cewa tunda tasirin kowane mu'amala da muhallin halittu yawanci ƙarami ne, masu bincike dole ne su yi ƙoƙarin rage kuskure kuma hanya ɗaya don guje wa kuskure shine ta hanyar auna ainihin tsayi da nauyi maimakon dogaro da rahotannin kai da suka shahara a yawancin karatu. . (Bukar, Kiba, Ƙarin, 2008.) Bugu da ƙari, Bouchard ya yi bayanin cewa "bambancin ɗan adam," gami da "ƙaddarar ilimin halittu" a cikin wasu don zama mai sauƙin kamuwa da nauyi ko asarar nauyi, shine "cikakken abin buƙata" a cikin neman kowane hulɗar muhalli da don ganewa na ƙarshe na takamaiman kwayoyin halitta. (Bouchard, 2008)

A cikin shekaru, mutane da yawa sun kirkiro abin da ake kira rajista biyu na dubban MZ da DZ tagwaye, gami da waɗanda ke Norway, Sweden, da Finland, kuma a cikin Amurka, (misali National Academy of Sciences-National Research Council (NAS-NRC) Twin Registry; Minnesota Registry, da Vietnam-Era Twin Registry. .) Mashahurin mai binciken kiba Albert (Mickey) Stunkard, alal misali, yayi amfani da rejista na tagwayen Sweden da Danish don wasu karatun sa. (Yau, NEJM , 2014) Stunkard et al ( JAMA , 1986) ya kuma yi amfani da Rajistar NAS-NRC don kimanta sama da tagwayen 1900 MZ da sama da tagwayen 2000 DZ don tantance gudummawar kwayoyin halitta zuwa tsayi, nauyi, da BMI a cikin binciken bin dogon lokaci (shekaru 25), tare da ƙarshe, "Kiba na dan adam yana karkashin kulawar kwayoyin halitta mai karfi." Masu binciken sun yarda, kodayake, ƙididdigar gado na iya zama abin zargi, tare da rashin ƙima da wuce gona da iri wataƙila saboda, alal misali, tsakanin sauran hanyoyin nuna son kai, ga kurakurai a cikin kafa zygosity ko kuma har ma da haɗaɗɗiyar jima'i (wanda ma'aurata kan yi aure Abokin aikin gini iri ɗaya.) Heymsfield da abokan aiki (Allison et al, Halittar Halittu , 1996) sun kuma jaddada cewa "daidaitattun ƙirar tagwaye" don kiba ba lallai ne sun haɗa da bayanai kamar ma'aunin ma'aurata ba kuma ko haɗuwar jima'i (watau, bazuwar bazuwar) na iya shafar ƙimar gado.

A cikin karatun tagwayen su, Stunkard et al ( NEJM, 1990) an kimanta nau'i -nau'i guda 93 na tagwaye masu kama da juna (ɗaya daga cikin ingantattun hanyoyin tantance mahimmancin rabe -raben halittu daga na muhallin raba); Tagwayen tagwaye guda 154 an yi renon su tare; An halicci ma'aurata 'yan uwan ​​juna guda 218, kuma ma'aurata' yan uwan ​​juna guda 208 sun taru tare, dukkansu sun fito ne daga Rijistar Sweden wanda ya haɗu da karatun tagwaye tare da karatun tallafi. An kimanta tagwaye a ƙarshen shekarun 50, tare da mata 60%. Masu binciken sun lura cewa, koda lokacin da aka tayar da tagwaye, suna iya yin kama da juna idan yanayin tarbiyyar su yayi kama (misali idan an sanya tagwaye "zaɓi" a cikin gidajen da suka yi kama da na iyayensu na asali.) Daga cikin waɗannan tagwayen waɗanda suka rabu da iyayensu na asali, kusan rabin tagwayen sun rabu a shekarar farko ta rayuwa, galibi saboda mutuwa, cuta, ko wahalar kuɗi a cikin dangin asalin. Stunkard et al sun sami tabbaci mai ƙarfi ga tasirin gado a kan BMI, kuma sun gano cewa tasirin kwayoyin halitta yana ƙaruwa a duk nau'ikan nau'ikan nauyi, watau, daga waɗanda ke bakin ciki zuwa waɗanda ke kiba. Sun kuma lura cewa tagwaye masu kama iri ɗaya suna da alaƙa tsakanin 0.70 ga maza da 0.66 ga mata don BMI kuma sun kammala a cikin wannan binciken cewa yanayin ƙuruciya ba shi da tasiri ko ma tasiri. Suna yin taka tsantsan, ko da yake, "heritability ba ya nufin rashin canzawa, tasirin kwayoyin halitta mara canzawa," amma tasirin kwayoyin halitta a ƙarƙashin wasu yanayin muhalli. (Stunkard et al, 1990) Tare da waɗannan layin, Allison, Heymsfield da abokan aiki (Faith et al, Jaridar Kiba ta Duniya, 2012) sun jaddada mahimmancin yin la’akari da mahallin ma'auni wanda yanayin muhallin da ke cikin ƙirar binciken (misali karantawa tagwaye yayin cin su) na iya yin tasiri ga sakamako.

A cikin shekaru da yawa, Allison, Heymsfield da abokan aikinsu sun yi amfani da ƙirar tagwayen don tantance alaƙar abin da ake kira tsarin gine -gine zuwa muhalli, gami da lokacin mahaifa (Allison et al, Jaridar Duniya ta Kiba da Ciwon Haɓakar Metabolic , 1995.) Sun kuma yi amfani da wannan ƙirar don nazarin ƙimar jikin mutum da hawan jini (Allison et al, Jaridar American Genetics Medical, 1995); ƙididdigar taro na jiki a cikin samfurin tagwayen yara (Faith et al, Likitan yara, 1999); Abincin caloric (Faith et al, Halayen Halitta, 1999); da cin abinci mai sarrafa kansa (Faith et al, Jaridar Kiba ta Duniya , London , 2012)

Layin ƙasa : Nazarin tagwaye ya samo asali ne daga lokacin Sir Francis Galton, wanda ya ba da shawarar yin amfani da tagwaye don bambance illolin yanayi daga tarbiyya, a ƙarshen karni na 19. Masu bincike sun yi amfani da su ba daidai ba, kamar su Nazis lokacin Yaƙin Duniya na II. A tarihi, mafi mahimmancin bincike na farko don fannin kiba ya fito ne daga Dr. Claude Bouchard et al, wanda ya kimanta tagwaye iri ɗaya (monozygote) a ƙarƙashin yanayin kula da marasa lafiya a cikin binciken karatun overfeeding na Quebec, kuma daga Mickey Stunkard et al, wanda ya tantance duka tagwayen monozygotic da dizygotic don rarrabe muhalli daga tasirin kwayoyin halitta, a cikin kira classic tagwaye zane.

Da fatan za a lura: Wannan wani bangare ne na blog mai kashi biyu akan amfani da tagwaye a bincike akan kiba. Sashe na II zai yi bincike sosai game da amfani da ƙirar co-twin wanda ɗayan tagwaye iri ɗaya ke rarrabuwa don sifa idan aka kwatanta da ɗayan. Don godiya ta musamman ga waɗanda suka taimaka wajen shirya blogs I da II, duba blog II.