Los ntawm ib nrab ntawm lub xyoo pua mus txog rau thaum pib ntawm lub xyoo pua 20, qhov kev tshawb fawb ntawm lub keeb tau muaj kev txhim kho ntau heev.
1. Xyoo 1875, tus kws tshaj lij German botanist EA Strassburger tau xub piav qhia txog cov khoom xim hauv cov nroj tsuag hlwb thiab xaus lus tias tib cov nroj tsuag muaj qee tus naj npawb ntawm cov khoom xim.
2. Xyoo 1880, Baranetsky tau piav qhia txog cov qauv kauv ntawm cov khoom muaj xim, thiab Pfitzner nrhiav pom cov xim sib txawv rau xyoo tom ntej.
3. Xyoo 1885, kws tshaj lij German C. Lable pom zoo txoj cai tsis tu ncua ntawm cov khoom muaj xim ntau.
4. Xyoo 1888, W. Waldell tso npe rau cov khoom muaj xim hauv keeb kwm li keeb kwm.
5. Xyoo 1891, kws tshaj lij German H. Henkin tau pom X cov chromosome hauv cov phev ntsha ntawm kab.
6. Xyoo 1902, WL Stevens, EB Wilson thiab lwm tus tau pom lub Y chromosome.
Qhov tshwm sim ntawm chav faib tau txais kev saib xyuas lub sijhawm no thiab tau ua tib zoo tshawb nrhiav.
1. Xyoo 1867, tus German botanist W. Hofmeister nyob hauv cov nroj tsuag, thiab A. Schneider nyob hauv cov tsiaj xyoo 1873. Lawv feem piav qhia txog kev faib tawm ncaj ncaj hauv ntau yam.
2. Xyoo 1882, German cytologist W. Fleming tau thov lub sijhawm mitosis los hloov cov kabmob ncaj qha tom qab pom qhov kev faib tawm ntev ntawm cov chromosomes. E. Heuzer piav qhia txog qhov faib cov chromosomes thaum faib ncaj qha; Tom qab nws, EA Strassburger muab faib mitosis rau hauv: thaum ntxov, nruab nrab, lig, thiab lub davhlau ya nyob twg; nws thiab lwm tus kws tshawb fawb kuj tau pom meiosis hauv cov nroj tsuag, thiab tom qab kev tshawb fawb ntxiv, thaum kawg lawv cais haploid thiab diploid. Cov lej ntawm cov chromosomes.
3. Xyoo 1933, H. Bauer nrhiav pom polytene chromosomes hauv Malpiki lub raj hlwb ntawm yoov tshaj cum.
4. Xyoo 1934, TS Payint nrhiav tau cov qauv no hauv Drosophila, thiab RL King thiab HW Beams hauv Chironomid.
Polytene chromosomes yog cov chromosomes loj loj uas muaj nyob hauv qee cov qog ntshav ntawm Diptera larvae. Hauv Drosophila, lawv qhov ntev yog li 100 zaus ntawm cov chromosomes ib txwm, thiab txhua lub chromosome muaj ntau (txog li 400) Nws yog los ntawm cov xim dyed, qhia cov xim tsaus nti thiab cuam tshuam txog kev cuam tshuam ntawm tag nrho cov chromosome. Nws tsim tau vim yog mitosis hauv lub nucleus (tsuas yog cov chromosomes tau muab faib tab sis tsis yog nuclei), yog li txhua polyline chromosome yog qhov tseeb tsim los ntawm ntau cov chromosomes. Cov chromosome zoo li loj, uas yoog txoj kev tsom xam ntawm cov qauv zoo ntawm cov chromosome. Ntxiv rau, cov haujlwm kev ua haujlwm ntawm polytene chromosomes tuaj yeem txiav txim siab raws li kev ua npuas o.
Nws tsis yog txog rau xyoo 1970 uas nucleosomes raug pom nyob rau hauv lub tshuab hluav taws xob; tsis ntev tomqab ntawd, suav nrog cov tshuaj rho tawm biochemical, nws tau pom tias cov chromosomes hauv cov metaphase yog cov npe hu ua scaffold protein ua qhov tseem ceeb, thiab cov DNA fibers tau ncab los ua spirals.