Amaphethini ayisisekelo wefa labalingiswa, esungulwe nguG. Mendel: incazelo nemisebenzi

Abantu babelokhu benesithakazelo kumaphethini wefa labalingiswa. Kungani izingane zibukeka njengabazali bazo? Ingabe kukhona ingozi yokudluliselwa kwezifo ezifa? Lezi zindaba eziningi nezinye eziningi zahlala ngaphansi kwesihenqo semfihlakalo kuze kube sekhulwini le-XIX. Ngaleso sikhathi uMendel waphumelela ekuqoqeni lonke ulwazi oluqoqiwe ngalesi sihloko, futhi nangokusungula ukuhlolwa okunzima okuhlaziya ukusetha amaphethini athile.

Umnikelo kaMendel ekuthuthukiseni izakhi zofuzo

Amaphethini ayisisekelo wefa lezimpawu yizimiso ngokusho ukuthi izici ezithile zidluliselwa eziphilayo eziphilayo kumzali. Ukutholakala kwabo nokuqalwa okucacile kuwukufaneleka kukaGregor Mendel, owenza ucwaningo oluningi ngalolu daba.

Ukuphumelela okuyinhloko kososayensi kuwubufakazi bezinto ezicacile zezici zokufa. Ngamanye amazwi, isakhi esiqondile sibhekene nesici ngasinye. Amabalazwe okuqala akhiwe ngamabele kanye noDrosophila. Leli yinto ejwayelekile yokwenza izivivinyo zofuzo.

Imikhawulo ye-Mendel ayikwazi ukuxoshwa, njengoba ososayensi basekhaya bethi. Ngakho-ke, isazi sezakhi ezidumile uTimofeev-Resovsky sathi uMendel wayengowokuqala owaqhuba ukuhlolwa okuyisisekelo futhi wanikeza incazelo enembile yezimo ezazikhona ngaphambili ezingeni lezinkolelo. Ngakho-ke, kungathathwa njengephayona lokucabanga ngezibalo emkhakheni wezinto eziphilayo kanye nezakhi zofuzo.

Abadluli phambili

Kubalulekile ukuphawula ukuthi amaphethini wefa lezici ngokusho kukaMendel azenzelwe endaweni engenalutho. Ucwaningo lwakhe lwalusekelwe ekucwaningweni kwabaphambili bakhe. Kubalulekile ukukhuluma ikakhulukazi ososayensi abalandelayo:

• UJ. Goss wazama ukhonkwane, ewela izitshalo ngezithelo zembala ehlukahlukene. Kungenxa yalezi zifundo ukuthi imithetho yokufaniswa kwesizukulwane sokuqala semvelo, kanye nokubusa okungaphelele, yatholwa. U-Mendel wanciphisa kuphela futhi waqinisekisa lesi sizathu.
• U-Augustin Sarge ungumlimi wezitshalo oye wakhetha amasiko amathanga ngenxa yokuhlolwa kwakhe. Wayengowokuqala ukufunda izici zefa, hhayi ngokuhlangene, kodwa ngokwehlukana. Uthi azihlangani nomunye lapho ehambisa izici ezithile. Ngakho-ke, i-heredity ihlala njalo.
• U-Noden wenza ucwaningo ngezinhlobo ezahlukene zezitshalo ezinjenge-dope. Ehlaziya imiphumela, wathola kudingekile ukukhuluma ngokutholakala kwezibonakaliso ezivelele, okuyizikhathi eziningi ezizobhekana nazo.

Ngakho-ke, ngekhulu le-XIX, izimo ezinjalo njengokubusa, ukufanana kwesizukulwane sokuqala, kanye nokuhlanganiswa kwezimfanelo ezinhlobonhlobo ezalandela zaziwa. Noma kunjalo, kwakungekho imithetho yonke. Lokhu kuhlaziywa kolwazi olutholakalayo kanye nokuthuthukiswa kwendlela yokucwaninga ethembekile okuyiyona mfanelo esemqoka kaMendel.

Izindlela zomsebenzi zikaMendel

Amaphethini wefa lezimpawu zikaMendel ahlelwe ngenxa yocwaningo oluyisisekelo. Umsebenzi wesosayensi wenziwa kanje:

• Izici ezizimele zazingacatshangwanga ngokubanzi, kodwa ngokwehlukana;
• Ukuze kuhlaziywe, izici ezihlukile kuphela ezikhethiwe ezimelela umehluko omkhulu phakathi kwezinhlobonhlobo (yilokho okwenza kwenzeke ukuthi kuchaze ukujwayela kwenqubo yefa ngokucacile);
• Ucwaningo lwaluyisisekelo (uMendel uphenyo inqwaba yezinhlanzi ezibili ezihlanzekile nezama-hybrid, bese ziwela "inzalo"), okwakwazi ukukhuluma ngomgomo wemiphumela;
• Ukusetshenziswa kwezindlela ezinembile ekuhloliseni idatha etholakalayo (usebenzisa ulwazi emkhakheni wezintambo ezingenzeka, uMendel unciphise inkomba yokungaphambuki okungahleliwe).

Umthetho wokufaniswa kwemifino

Uma sicabanga ngamaphethini wefa lezimpawu, kufaneleka ukunaka ngokukhethekile ukulingana kwenhlawulo yesizukulwane sokuqala. Kutholakale ngesipiliyoni, lapho kuhamba khona amafomu omzali ngesibonakaliso esisodwa (ifomu, umbala, njll).

UMendel wanquma ukuqhuba ukuhlolwa kwezinhlobonhlobo zama-peas - ngezimbali ezibomvu nezimhlophe. Ngenxa yalokho, izinhlamvu zesizukulwane sokuqala zathola ama-inflorescences obomvu. Ngakho-ke, kwakukhona isisekelo sokukhuluma mayelana nokuba khona kwezici eziqakathekile nezingaphelele.

Kuyadingeka ukuthi lokhu okuhlangenwe nakho kukaMendel kwakungewona owodwa. Wasebenzisa ukuhlola izitshalo ngamanye ama-shades of inflorescences, ngezinhlobo ezahlukene zezithelo, ubukhulu obuhlukahlukene be-stem nezinye izinto ezihlukahlukene. Okuhlangenwe nakho, wakwazi ukufakazela ukuthi yonke inhlawulo ye-oda lokuqala iyinifomu futhi ibonakala ngesici esibalulekile.

Ukubusa okungaphelele

Phakathi nokufunda umbuzo onjalo njengamaphethini wefa lezimfanelo, ukuhlolwa kwenziwa kokubili ezitshalweni naseziphilayo eziphilayo. Ngakho-ke, kwakungenakwenzeka ukubeka ukuthi akuwona njalo izimpawu zikhona ebuhlotsheni bokubusa nokucindezela okuphelele. Isibonelo, lapho uwela izinkukhu ezimnyama nezimhlophe, kungenzeka ukuthi uthole inzalo eluhlaza. Ngakho kwakukhona ezinye izitshalo, lapho izinhlobo ezinemibala ephuzi neyomhlophe echwebeni zanikeza i-pink shades. Ngakho-ke, isimiso sokuqala singalungiswa, sibonisa ukuthi isizukulwane sokuqala semvelo siyoba nezici ezifanayo, futhi zingase ziphakathi.

Izici zokuchitha

Ukuqhubeka ukuphenya amaphethini wefa labalingiswa, uMendel wathola kudingekile ukuwela izinzalo ezimbili zesizukulwane sokuqala (heterozygous). Ngenxa yalokho, inzalo yamukelwa, enye yayo yayinamandla, kanti enye yayingaphindaphindi. Kusukela lokhu kungaphetha ngokuthi isibonakaliso sesibili sesizukulwane sokuqala semvelo asizange sinyamalale nhlobo, kodwa sigxiliwe kuphela futhi singase sibonakale esizalweni esilandelayo.

Ifa elizimele

Imibuzo eminingi iphakamisa amaphethini wefa lezimfanelo. Ukuhlolwa kukaMendel nakho kwabathinta abantu, okuhluke komunye nomunye ngezizathu eziningana. Kulowo nalowo, amaphethini wangaphambilini abhekwe. Kodwa, ngokucabangela izici zezimpawu, kwakungenakwenzeka ukudalula noma yimaphi amaphethini phakathi kokuhlanganiswa kwawo. Ngakho-ke, kunesizathu sokukhuluma ngokuzimela kwefa.

Umthetho wokuhlanzeka kwama-gametes

Amaphethini athile wefa labalingiswa, asetshenziswe nguMendel, ayemane nje ayingqayizivele. Kuwumbuzo womthetho wokuhlanzeka kwe-gametes, equkethe ukuthi iqukethe i-allele eyodwa kuphela kusuka kulababili okuqukethwe kwisigca somzali.

Ngesikhathi sikaMendel, kwakungekho izindlela zobuchwepheshe ukuqinisekisa lesi sizathu. Noma kunjalo, usosayensi wakwazi ukwakha isitatimende jikelele. Isisekelo salo sisekholweni lokuthi ekubunjweni kwenhlanzi, izici zefa zihlala zingashintshi, futhi azihlanganisi.

Izimo ezibalulekile

I-Genetics yisayensi ehlola amaphethini wefa labalingiswa. UMendel wenza iqhaza elikhulu ekuthuthukisweni kwalo, esebenzise izinhlinzeko eziyisisekelo kulo magazini. Noma kunjalo, ukuze kugcwaliseke, izimo ezilandelayo ezibalulekile kumele zigcinwe:

• Amafomu okuqala kumele abe yi-homozygous;
• Ukungafani kwezimpawu;
• Amathuba afanayo ekwakhiweni kwezinsizakalo ezahlukene e-hybrid;
• Ukulingana okulingana kwe-gametes;
• Uma i-gametes ehlanganisiwe ihlangene ngokungahleliwe;
• Ama-zygotes anehlanganisela ehlukene yezakhi zofuzo afanayo ngokulinganayo;
• Inombolo yabantu ngabanye wesizukulwane sesibili kufanele ibe ngokwanele ukuthatha imiphumela njengokwemthethweni;
• Ukubonakaliswa kwezici akufanele kuncike emthethweni wezimo zangaphandle.

Kufanele kuqaphele ukuthi iningi lezinto eziphilayo, kuhlanganise nabantu, lihambisana nalezi zici.

Amaphethini wefa lezimfanelo kubantu

Naphezu kokuthi i-genetic principles ekuqaleni yaphenywa ngokusebenzisa izitshalo njengesibonelo, ibuye isebenzise izilwane nabantu. Kufanele kuqaphele izinhlobo ezinjalo zefa:

• I-Autosomal eyinhloko ifa lezimfanelo ezivelele ezitholakala ngaphakathi nge-autosomes. Kulesi simo, i-phenotype ingaba kakhulu noma ingabonakali. Ngalolu hlobo lwefa, amathuba okuba ingane etholakale i-allele pathological yomzali ingu-50%.
• I-Autosomal ngokweqile - ifa lezibonakaliso zesibili ezihlobene nama-autosomes. Izifo zibonakaliswa nge-homozygotes, futhi zombili izinhlangothi zithintekile.
• Uhlobo oluxhunyaniswe kakhulu lwe-X luchaza ukudluliswa kwezici ezivelele zezakhi ze-deterministic. Ngesikhathi esifanayo, abesifazane banamathuba amabili okuba nezifo njengamadoda.
• Uhlobo oluxhunyiwe lwe-X oluthile - ifa livela ngesibuthakathaka. Lesi sifo noma izibonakaliso zalo ngabanye zivele zivela enzalweni yecansi yesilisa, nakwabesifazane kuphela e-homozygous state.

Imiqondo eyisisekelo

Ukuze uqonde ukuthi amaphethini wefa lezimpawu zikaMendel kanye nezinye izinqubo zezofuzo zisebenza kanjani, kufanelekile ukuzijwayeza ngezincazelo eziyisisekelo kanye nemibono. Lokhu kufaka lokhu okulandelayo:

• Isici esibaluleke kakhulu yisici esibaluleke kakhulu esisebenza njengesimo esinqumayo segesi futhi sivimbela ukuthuthukiswa kwabantu abadlulayo.
• Imfanelo ephindaphindiwe yisici esizuzwa njengefa, kepha asiyona into echaza.
• I-Homozygote - umuntu noma i-cell diploid, kuma-chromosomes lapho amangqamuzana afanayo wegesi aqukethwe khona.
• I-heterozygote iyinhlangano ye-diploid noma iseli ehlukanisa futhi inezinhlobonhlobo ezihlukahlukene ngaphakathi kwesiginci esifanayo.
• I-Allele ingenye yefomu ehlukile yegesi ekhona endaweni ethile ye-chromosome futhi ibonakala ngokulandelana okuyingqayizivele kwe-nucleotides.
• I-Allele iyinhlangano yezakhi zofuzo ezisezindaweni ezifanayo zama- chromosomes ezinama-homologous futhi zilawula ukuthuthukiswa kwezici ezithile.
• Izakhi ze-non-allelic zitholakala ezingxenyeni ezihlukene zama-chromosomes futhi zibhekene nokubonakaliswa kwezici ezihlukahlukene.

Isiphetho

I-Mendel yakhelwe futhi ngokusebenza kwayo yabonisa amaphethini ayisisekelo yefa labalingiswa. Incazelo yabo inikezwa ngesibonelo sezitshalo futhi lula kancane. Kodwa ngokwenzayo kulungile kuzo zonke izinto eziphilayo.