Mutace

=20 Za ka=9Edou vadou =E8i genetick=FDm onemocn=ECn=EDm se skr=FDv=E1 = ur=E8it=E1 chyba=20 v genotypu*=20 jedince. Chybu ozna=E8ujeme za mutaci, n=ECkter=E9 se v=F9bec = neprojev=ED, n=ECkter=E9 jsou=20 pozitivn=ED a maj=ED vliv na evoluci, ale v=ECt=9Aina jich je = negativn=EDch a vyvol=E1v=E1=20 vznik vad a onemocn=ECn=ED.

Mutace m=F9=9Eeme=20 rozd=EClit

Spont=E1nn=ED=20 =96 vznikaj=ED samovoln=EC p=F8i replikaci DNA a nejsou ovlivn=ECny = vn=ECj=9A=EDm prost=F8ed=EDm.=20
Indukovan=E9=20 =96 jsou vyvol=E1ny vn=ECj=9A=EDmi mutagenn=EDmi faktory =3D MUTAGENY =

=D8ad=EDme sem=20 UV, RTG z=E1=F8en=ED, chemick=E9 l=E1tky (areny, t=EC=9Ek=E9 kovy, =20 &n= bsp; peroxidy=85)

D=E1le mutace=20 d=ECl=EDme na:

1.=20 Genov=E9 (bodov=E9) mutace =96 p=F8edstavuj=ED zm=ECnu = v jednom genu.=20 M=F9=9Ee postihnout jeden nebo n=ECkolik nukleotid=F9 DNA ur=E8it=E9ho = genu, p=F8i=E8em=9E=20 nedoch=E1z=ED ke zm=ECn=EC po=F8ad=ED a polohy gen=F9.

= ; = &= nbsp; =20 I. =20 Nukleotidov=E1 substituce =96 v=FDm=ECna = nukleotid=F9 RNA=20 nebo nukleotidov=FDch p=E1r=F9 DNA v nukleov=FDch kyselin=E1ch. = Prob=EDh=E1 dv=ECma=20 zp=F9soby:

Tranzice=20 =96 v=FDm=ECna purinov=E9ho nukleotidu za purinov=FD a pyrimidinov=E9ho = za pyrimidinov=FD

&nbs= p; =20 A za G nebo C za T

Transverze=20 =96 v=FDm=ECn purinov=E9ho nukleotid=F9 za pyrimidinov=FD a = pyrimidinov=FD za purinov=FD

&nbs= p; =20 A, G za C, T

&nbs= p; =20 (pozn. purinov=E9 nukleotidy =96 A, G, pyrimidinov=E9 =96 C, T, = U)

Substitu=E8n=ED=20 mutace se mohou, ale i nemus=ED fenotypov=EC projevit. Mutace, kter=E9 = se fenotypov=EC=20 neprojev=ED ozna=E8ujeme jako tich=E9 mutace (neutr=E1ln=ED). Tyto = mutace spo=E8=EDvaj=ED ve=20 zm=ECn=EC kodonu, ale v d=F9sledku degenerovanosti genetick=E9ho = k=F3du nedoch=E1z=ED ke=20 zm=ECn=EC aminokyseliny nebo dojde ke zm=ECn=EC aminokyseliny, kter=E1 = se neprojev=ED ve=20 funkci polypeptidov=E9ho =F8et=ECzce.

a) =20 Nukleotidov=E1 synonymn=ED substituce

P=F9vodn=ED=20 DNA &nbs= p; = ;=20 3=B4 =20 TAT ACG GGC AAT 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC CCG UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Pro =96 Leu

zmutovan=E1 DNA=20 &nbs= p; =20 3=B4 =20 TAT ACG GGT AAT = 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC CCA UUA =20 3=B4 =20

protein &nbs= p; = ; = =20 Ile =96 Cys - Pro =96 Leu

b) =20 Nukleotidov=E1 neutr=E1ln=ED substituce

P=F9vodn=ED=20 DNA &nbs= p; = ;=20 3=B4 =20 TAT ACG GGC AAT 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC CCG UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Pro =96 Leu

zmutovan=E1 DNA=20 &nbs= p; =20 3=B4 =20 TAT ACG AGC AAT = 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC UCG UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Ser =96 Leu

V p=F8=EDpad=EC=20 =9Ee substitu=E8n=ED mutac=ED dojde ke zm=ECn=EC nukleotidu ( kodonu), a = n=E1sledn=EC ke zm=ECn=EC=20 funkce v=FDsledn=E9ho polypeptidov=E9ho =F8et=ECzce, ozna=E8ujeme tyto = mutace jako m=ECn=EDc=ED=20 smysl kod=F3nu.

a) =20 Kodon s pozm=ECn=ECn=FDm smyslem

P=F9vodn=ED=20 DNA &nbs= p; = ;=20 3=B4 =20 TAT ACG TGC AAT 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC ACG UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Thr =96 Leu

zmutovan=E1=20 DNA &nbs= p; =20 3=B4 =20 TAT ACG CGC AAT = 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC GCG UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Ala =96 Leu

b) =20 Mutace nesmysln=E1 (beze smyslu)

P=F9vodn=ED=20 DNA &nbs= p; = ;=20 3=B4 =20 TAT ACG ACG AAT 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC UGC UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Cys =96 Leu

zmutovan=E1=20 DNA &nbs= p; =20 3=B4 =20 TAT ACG ACT AAT = 5=B4

mRNA &nbs= p; = ; =20 5=B4 =20 AUA UGC UGA UUA =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 Cys - Stop

= ; = &= nbsp; =20 II. =20 Posunov=E9 mutace

Jedn=E1 se o mutace, = kter=E9 maj=ED za=20 n=E1sledek posun =E8tec=EDho r=E1mce p=F8i proteosynt=E9ze a = rozli=9Aujeme dva z=E1kladn=ED=20 typy:

=20 Delece =96 je ztr=E1ta jednoho nebo v=EDce nukleotid=F9=20 z nukleotidov=E9 sekvence. V=FDsledkem je posun =E8tec=EDho r=E1mce = doleva.

P=F9vodn=ED DNA &nbs= p; =20 3=B4 =20 TAT ACG TGC AAT CGA &nbs= p; =20 5=B4

mRNA &nbs= p; =20 5=B4 =20 AUA UGC ACG UUA GCU &nbs= p; =20 3=B4

protein &nbs= p; = ; = =20 Ile =96 cys =96 thr = - leu - =20 ala

zmutovan=E1 DNA =20 3=B4 =20 TAT ACG GCA ATC GA &nbs= p; =20 5=B4

mRNA &nbs= p; =20 5=B4 =20 AUA UGC CGU UAG CU &nbs= p; =20 3=B4 &nbs= p; =20

protein &nbs= p; = ; = =20 ile =96 cys =96 = arg- Stop=20

=20 Inzerce (adice) =96 je vlo=9Een=ED jednoho nebo v=EDce = nukleotid=F9 do=20 nukleotidov=E9 sekvence.V=FDsledkem je posun =E8tec=EDho r=E1mce = doprava.

P=F9vodn=ED DNA &nbs= p; =20 3=B4 =20 TAT ACG TGC AAT CGA &nbs= p; =20 5=B4

MRNA &nbs= p; =20 5=B4 =20 AUA UGC ACG UUA GCU &nbs= p; =20 3=B4

Protein &nbs= p; = ; =20 ile- cys - thr - =20 leu - ala =20

zmutovan=E1 DNA =20 3=B4 =20 TAT ACG TGC AAA TCG A =20 5=B4

mRNA &nbs= p; =20 5=B4 =20 AUA UGC ACG UUU AGC U =20 3=B4

protein &nbs= p; = ; = =20 ile - =20 cys - thr - phe- ser

2.=20 Chromozomov=E9 mutace (aberace)

Strukturn=ED aberace chromozom=F9

Jsou to=20 morfologick=E9 zm=ECny chromozom=F9, kter=E9 vedou ke zlom=F9m a = k p=F8estavb=E1m=20 struktury chromozom=F9.Obvykle p=F8i nich doch=E1z=ED ke ztr=E1t=E1m = nebo k p=F8em=EDst=ECn=ED=20 v=ECt=9A=EDch =84blok=F9=93 genetick=FDch informac=ED, = odpov=EDdaj=EDc=EDch v=ECt=9A=EDm skupin=E1m gen=F9.=20 Chromosomy mohou b=FDt poru=9Aeny ionizuj=EDc=EDm z=E1=F8en=EDm, = mechanick=FDmi i chemick=FDmi=20 l=E1tkami.V z=E1vislosti v kter=E9 =E8=E1sti bun=EC=E8n=E9ho cyklu = dojde k poru=9Aen=ED,=20 jsou tyto zm=ECny, bu=EF replikov=E1ny do obou sestersk=FDch = chromatid*=20 nebo z=F9st=E1vaj=ED omezeny jen na jednu chromatidu.

Chromozomov=E9=20 aberace m=F9=9Eeme rozd=EClit na:

a) =20 Delece =96 odlomen=ED =E8=E1sti chromozom=F9 a = jej=ED n=E1sledn=E1=20 degradace v cytoplazm=EC

b) =20 Duplikace =96 odlomen=E1 =E8=E1st chromozom=F9 = se enzymaticky=20 p=F8ipoj=ED na sesterskou &n= bsp; &nb= sp; &nbs= p; = ; =20 chromatidu &n= bsp; &nb= sp; =20

c) =20 Inverze =96 zlom prob=EChne na dvou m=EDstech = chromatidy,=20 odlomen=E1 =E8=E1st se oto=E8=ED a znovu spoj=ED

d) =20 Translokace =96 odlomena =E8=E1st se p=F8ipoj=ED = na jin=FD=20 chromozom

Delece &nbs= p; = ; = &= nbsp; &n= bsp; =20 Duplikace

Inverze &nbs= p; = ; = &= nbsp; &n= bsp; =20 Translokace

Numerick=E9=20 aberace chromozom=F9.

Jedn=E1 se o=20 po=E8etn=ED odchylky chromozom=F9 v j=E1d=F8e somatick=E9 bu=F2ky = nebo gamet=EC.=20 Rozezn=E1v=E1me aneuploidii a polyploidii.

Aneuploidie=20

Vznik=E1=20 translokac=ED ur=E8it=E9ho chromozomu na jin=FD chromozom (splynut=EDm = dvou chromozom=F9=20 v jeden). Nebo nondisjunkc=ED, co=9E znamen=E1 neodd=EClen=EDm = homologn=EDch chromozom=F9=20 p=F8i mei=F3ze, nebo tak=E9 p=F8i mit=F3ze (vznik=E1 monosomie, = nullisomie, trisomie,=20 tetrasomie, atd.)

Polyploidie

Je = stav p=F8i=20 n=ECm=9E je v j=E1d=F8e vy=9A=9A=ED po=E8et =FApln=FDch = chromozomov=FDch sad ne=9E dv=EC, tj.=20 triploidie (3n), tetraploidie (4n) a oktoploidie (8n) a jin=E9.