Qhov sib txawv tseem ceeb ntawm Holliday Model thiab Meselson-Radding Model yog qhov Holliday qauv qhia tsim cov symmetric heteroduplex thaum Meselson-Radding qauv qhia tsim cov asymmetric heteroduplex.
Recombination yog txheej txheem uas cov khoom tawg ntawm DNA tau tawg thiab rov ua dua los tsim cov kev hloov kho caj ces. Cov txheej txheem no tsim muaj kev sib txawv ntawm cov noob caj noob ces thiab qhia txog qhov sib txawv ntawm DNA sib txawv ntawm cov kab mob sib txawv. Holliday Model thiab Meselson-Radding Model yog ob qho qauv sib txawv uas hais txog cov kauj ruam tseem ceeb ntawm kev sib koom ua ke.
Hnub so Model dab tsi?
Holliday qauv yog tus qauv npaj los ntawm Robin Holliday uas tso nyiaj rau heteroduplex tsim thiab noob hloov pauv thaum lub sijhawm rov ua dua. Cov qauv no nthuav tawm cov kauj ruam tseem ceeb ntawm kev sib koom ua ke, uas suav nrog kev sib koom ua ke ntawm homologous duplexes, tsim ntawm heteroduplex thiab tsim ntawm kev sib koom ua ke, ceg tsiv teb tsaws, thiab kev daws teeb meem.
Daim duab 01: Kev Sib Tw ntawm Hnub So Qauv
Cov txheej txheem ntawm Holliday qauv tsim pib nrog ob homologous chromosomes uas tsim cov duplex DNA ua ke nrog cov kab ke zoo sib xws nyob ib sab. Tom ntej no, ib qho endonuclease txiav cov cheeb tsam sib thooj ntawm homologous strands ntawm cov khub duplexes. Tom qab ntawd qhov kev txiav xaus dissociate los ntawm lawv complementary strands. Ntawm no, lub arc strand invades lwm duplex. Tom qab ntawd cov cheeb tsam txiav raug kaw nrog DNA ligase thiab ua rau muaj kev sib koom ua ke ruaj khov. Qhov tseem ceeb ntawm cov qauv no yog tias nws kho ob lub duplexes sib npaug. Yog li ntawd, nws tsim ib tug symmetric heteroduplex.
Meselson-Radding Model yog dab tsi?
Meselson-Radding Model yog tus qauv uas piav qhia txog kev sib txuas ntawm noob los ntawm asymmetric heteroduplex. Cov qauv no conceptualizes dav genetic recombination thaum lub sij hawm meiosis ntawm tshiab replicated ob-stranded DNA. Ntawm no, endonuclease txiav ib txoj hlua ntawm ib tug ntxhais duplex. Lub 5 'kawg dissociates thiab tso cai rau synthesis ntawm tus tshiab 3'-kawg thiaj li yuav mus tas li tshem nws. Tom ntej no, qhov dawb 5 'kawg displaces homologue tam sim no nyob rau hauv lwm tus ntxhais duplex. Qhov no yog ua raws li kev txiav txim siab ntawm qhov kev hloov pauv thiab ligation ntawm thawj 5'-kawg mus rau qhov tshiab 3'-kawg ntawm qhov thib ob duplex. Thaum kawg, ligation ntawm qhov seem 3'- thiab 5'-kawg tshwm sim los ntawm kev sib hloov pauv cov kab tsis zoo, tso cai rau ceg tsiv teb tsaws thiab sib cais.
Dab tsi zoo sib xws ntawm Holliday Model thiab Meselson-Radding Model?
- Holliday qauv thiab Meselson-Radding qauv piav qhia cov txheej txheem recombination.
- Lawv suav nrog endonuclease thiab ligase kev ua haujlwm.
- Ob tus qauv Holliday thiab Meselson-Radding qauv suav nrog ntau cov kauj ruam.
- Ob daim ntawv heteroduplexes thaum lub sijhawm ua haujlwm.
- Lawv ua lub luag haujlwm tseem ceeb hauv kev sib txuas ntawm caj ces thiab kev sib txawv ntawm caj ces.
Qhov txawv ntawm Holliday Model thiab Meselson-Radding Model yog dab tsi?
Holliday qauv tawm tswv yim tsim ntawm symmetric heteroduplex, thaum Meselson-Radding qauv tawm tswv yim tsim cov asymmetric heteroduplex. Yog li, qhov no yog qhov sib txawv tseem ceeb ntawm Holliday qauv thiab Meselson-Radding qauv. Tus qauv Holliday tau thov los ntawm Robin Holliday, thaum Meselson thiab Radding tau thov tus qauv Meselson-Radding. Ntxiv mus, tus qauv chi yog tam sim no nyob rau hauv tus qauv Holliday, thaum nws tsis nyob hauv Meselson-Radding qauv.
Cov hauv qab no infographic nthuav tawm qhov sib txawv ntawm Holliday qauv thiab Meselson-Radding qauv hauv daim ntawv teev npe rau ib sab ntawm kev sib piv.
Summary – Holliday Model vs Meselson-Radding Model
Holliday qauv thiab Meselson-Radding qauv qhia cov tswv yim tsim heteroduplex thaum lub sijhawm rov ua dua. Tus qauv Holliday yog tus qauv npaj los ntawm Robin Holliday uas tso nyiaj rau kev sib xyaw heteroduplex tsim thiab hloov noob caj noob ces thaum rov ua dua. Meselson-Radding qauv conceptualizes dav genetic recombination thaum lub sij hawm meiosis ntawm tshiab replicated ob-stranded DNA. Ob qho qauv ua lub luag haujlwm tseem ceeb hauv kev sib xyaw ua ke thiab kev sib txawv ntawm caj ces. Yog li, qhov no qhia txog qhov txawv ntawm Holliday Model thiab Meselson-Radding Model.
