Morgan chromosomal ka'idar: definition, asali arziki da kuma siffofin

Me ya sa yara kama da iyayensu? Me ya sa wasu iyalai yada wasu cututtuka kamar launi makanta, polydactyly, hadin gwiwa hypermobility, cystic fibrosis? Me da yawan cututtuka da shafi kawai mata da sauransu - kawai maza? Yau mun san cewa amsoshin wadannan tambayoyi dole ne, a nemi a gadar hali, watau chromosomes cewa yaro yana karɓa daga kowane iyaye. Kuma tare da wannan ilimi, kimiyyar zamani da aka zamar masa dole ya Thomas Hunt Morgan - American itatuwa aure. Ya bayyana aiwatar da canja wurin kayyade bayanai da kuma ya ci gaba tare da abokan aiki chromosomal ka'idar gado (sau da yawa ake kira chromosome ka'idar Morgan), wanda ya zama mafificin dutsen gini na zamani itatuwa aure.

Tarihi na samu

Yana zai zama daidai ba ne a ce Thomas Morgan ne na farko da zama sha'awar da batun canja wurin kayyade bayani. A farko masu bincike suka yi kokarin fahimtar da muhimmancin chromosomes cikin gādon da za a iya gani a aikin Chistyakov, Beneden, Rabl a 70-80-ies na XIX karni.

Akwai wani microscopes haka iko don ya sami damar ganin chromosome tsarin. Kuma kalmar "chromosome" Sa'an nan, kuma, ya ba. An gabatar da Jamus masanin kimiyya Heinrich Valdeyr a 1888.

Jamus halitta Theodor Boveri a sakamakon ya gwajen tabbatar da cewa wajibi ne ga al'ada ci gaban na jiki ta al'ada don ta jinsunan yawan chromosomes, kuma su wuce haddi ko karancin take kaiwa zuwa tsanani malformations. A tsawon lokaci, ya ka'idar da aka brilliantly tabbatar. Za mu iya cewa da chromosome ka'idar T. Morgan samu ta masomin godiya ga bincike Boveri.

Fara na gudanar da bincike

Kira na data kasance ilmi a kan ka'idar gadar hali, to kari kuma ci gaba su gudanar da Thomas Morgan. Kamar yadda abu da ya gwajen da ya zabi da 'ya'yan gardama, da kuma ba da hatsari. A da m abu don nazarin na watsa kayyade bayanai - kawai hudu chromosome, da takin gargajiya, short tsawon rayuwa. Morgan fara yin bincike, ta amfani da tsabta Lines Kudaje. Ya zarar gano cewa jam sel na daya sa na chromosomes, cewa shi ne 2 maimakon 4. Yana Morgan kayyade yadda mace jima'i chromosome X, namiji - a matsayin Y.

Sex-nasaba gādo

Morgan ta chromosome ka'idar da ya nuna cewa akwai tabbataccen ãyõyin jima'i-nasaba. Fly, da wadda masana kimiyya da za'ayi masa gwaje-gwajen, wanda kullum yana da ja-ido, amma a sakamakon maye gurbi wannan gene a yawan mutane fari-sa ido mutane, kuma daga cikinsu akwai da yawa fiye da namiji. A gene, wanda shi ne alhakin da launi na gardama ido aka sarrafa a kan X chromosome, a kan Y-chromosome ba. Wannan shi ne, ta hanyar su tsallaka mãtã, daya X chromosome wanda yana da mutated gene, da kuma ferruginous namiji Yiwuwar gaban da hali a cikin zuriyarsa za a haɗa da kasa. A mafi sauki hanyar nuna wannan a kan zane:

• P: XX 'x X'Y.
• F _1: XX ', XY, X'X' X'Y.

X - mace jima'i chromosome ko gene ba tare da fari namiji ido. X 'chromosome gene fata na idanu.

Decipher mararraba sakamakon:

• XX '- ja-sa ido mace gene m da ido. Saboda gaban na biyu X-chromosome da mutated gene "overlaps" lafiya, da kuma bayyana wani phenotype fasalin.
• X'Y - fari-sa ido namiji, wanda ya karbi daga cikin uwa tasa ta X chromosome tare da mutant gene. By da ciwon daya kawai X-chromosome mutant hali kome don toshe, kuma ta bayyana a phenotype.
• X'X '- fari-sa ido mace chromosome gaji mutated gene daga uwa da uba. The mace kawai idan duka biyu X-chromosomes gudanar da gene fata na idanu, shi zai bayyana a cikin phenotype.

A chromosomal ka'idar gadar hali Thomas Morgan bayyana ginshikai na gado na da yawa kwayoyin cututtuka. Saboda X chromosome genes yawa fiye da a kan Y chromosome, an fahimci cewa shi ne alhakin mafi bayyanar cututtuka kwayoyin. A X chromosome daga uwar daukar kwayar cutar a matsayin maza da mata, tare da kwayoyin halittu da alhakin Properties na jiki, external alamun cutar. Tare da X-nasaba akwai wani Y-nasaba gādo. Amma da Y-chromosome ne kawai ga maza, saboda idan ta faru da wani maye gurbi, shi za a iya wuce a kawai don namiji zuriyarsa.

A chromosomal ka'idar gadar hali Morgan taimaka wajen fahimtar alamu na watsa daga kwayoyin cututtuka, duk da haka, da matsaloli hade tare da su magani, ba a yarda har yanzu.

crossover

A lokacin binciken, wani almajiri na Thomas Morgan Alfred Sturtevant gano sabon abu na mararraba-kan. Kamar yadda m gwaje-gwajen, sabon haduwa da genes faruwa saboda hayewa. Shi ya warware wani tsari nasaba gādo.

Kamar wancan chromosome ka'idar T. Morgan samu wani muhimmin matsayi - tsakanin homologue chromosomes auku mararraba-kan, kuma ta mita aka ƙaddara ta nisa tsakanin kwayoyin halittu.

shikan

Don systematize da sakamakon gwaje-gwajen da na masanin kimiyya, zai gabatar da ainihin matsayin da chromosomal ka'idar Morgan:

1. Alamun dogara ne a kan kwayoyin halittar da aiwatuwa a cikin chromosomes.
2. A genes na daya chromosome an wuce zuwa zuriya kama. A ƙarfi daga cikin mannewa ne mafi girma, da karami da nisa tsakanin kwayoyin halittu.
3. A homologue chromosomes lura sabon abu na mararraba-kan.
4. Sanin mita na tsallaka kan wani chromosome, za mu iya lissafta da nisa tsakanin kwayoyin halittu.

A matsayi na biyu daga cikin chromosomal ka'idar Morgan da kuma Morgan kira da mulki.

fitarwa

A binciken da sakamakon da aka sani brilliantly. Morgan ta chromosome ka'idar da aka nasara a ilmin halitta na karni na ashirin. A shekara ta 1933, domin gano rawar da chromosomes a gadar hali Nobel Prize aka bayar ga masanin kimiyya.

A 'yan shekarun baya, Thomas Morgan samu da Copley mindar for fice nasara a filin daga itatuwa aure.

Yanzu Morgan ta chromosome ka'idar gadar hali da aka yi karatu a makarantu. Ta kishin yawa articles da kuma littattafai.

Misalai tsunduma da kasa gādo

Morgan ta chromosome ka'idar ya nuna cewa da kaddarorin na jiki suna ƙaddara da genes hõrarru ne da shi. Na asali sakamakon cewa samu Thomas Morgan, ya ba da amsa ga wannan tambaya na canja wuri da cututtuka kamar hemophilia, Lowe ciwo, makanta, Bruttona cuta.

An gano cewa kwayoyin halittu na duk wadannan cututtuka da ake located a kan X chromosome da mata, wadannan cututtuka faruwa da yawa kasa akai-akai, kamar yadda da lafiya chromosome iya override da chromosome da cutar gene. Mata suka ba su sani ba, na iya zama yan dako da kwayoyin cututtuka, wanda aka sa'an nan bayyana a cikin yara.

A maza, X-nasaba cuta, ko phenotypic bayyanar cututtuka bayyana, domin babu lafiya X chromosome.

A chromosomal ka'idar gadar hali T. Morgan amfani a cikin bincike na iyali tarihi domin kwayoyin cututtuka.