Transmiterea caracterelor

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    11-Aug-2015
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genetica

Transcript of Transmiterea caracterelor

Transmiterea caracterelorGene: autozomale sau gonozomale normale (de tip salbatic) sau mutante dominante, recesive sau codominante

Genotip: heterozigot homozigot

Gene alele n cromosomii omologi

Genele alele snt situate n aceleai locusuri n perechile de cromosomi omologi unul de la forma printeasc masculin i altul de la cea femenin (cu excepia genotipurilor XY, XO)

Legile lui MendelLegea uniformitatii hibrizilor din F1(monohibridare) Legea segregarii caracterelor la indivizii din F2 Legea asortarii (segregarii) independente a caracterelor in dihibridare

Simbolica n genetic

P prini; x ncruciarea; - genotipul femel; F1,2,3 . generaia (1,2,3,); - genotipul mascul; A alela dominant a genei; a alela recesiv a genei; AA(aa) genotip homozigotat dup caracterul dominant (recesiv); Aa genotip heterozigotat dup un caracter.

Uniformitatea primei generaii de hibrizi

AA form printeasc homozigot dominant conform caracterului studiat; aa - form printeasc homozigot recesiv conform caracterului studiat; Aa Prima generaie de hibrizi

Genetic SegregationParentals: RR x rr F1 x F1: Rr x Rr

Rr

R

rr Rr Rr

r

R

r

R

r

RR

Rr Rr

R r

R r RR Rr Rr rr

Segregarea n F2 la ncruciarea monohibrid1.

Apariia n F2 a caracterului ,,disprut n F1P

2.

Aa GA

Aa

3.

aaA A

A

a

4.

Formele printeti snt heterozigote conform caracterului studiat; Gameii care se formeaz datorit procesului de meioz pot conine numai una din cele dou alele; n rezultatul combinrii libere a gameilor n F2 se manifest efectul de segregare 3:1 dup fenotip 1AA :2Aa :1aa dup genotip 3 : 1 - dup fenotip

A a

A a

a a

DIHIBRIDAREAChapter 9 Dihybrid CrossesSection 2 Genetic Crosses

Parentals: RRYY x rryyRY RY RY RY ry ry ry ry

ryRY RrYy

F1 x F1: RrYy xRY Ry rY ry

RrYy rY ry

RY Ry rY

RY

Ry

ry

1/16 RRYY 1/16 RRYy 1/16 RrYY 1/16 RrYy 1/16 RRYy 1/16 RRyy 1/16 RrYy 1/16 Rryy

1/16 RrYY 1/16 RrYy1/16 RrYy 1/16 Rryy

1/16 rrYY1/16 rrYy

1/16 rrYy1/16 rryy

27:9:9:9:3:3:3:1

Tipuri de gamei produi de un organism heterozigot pentru nloci

AaBb: 2n = 22 = 4 tipuri de gamei AB Ab Ba ab AaBbCC: 2n = 23 = 8 gamei ABC ABc AbC Abc aBC aBc abC abc AaBbCCDdEeFf : 2n = 26 = 64 gameicopyright cmassengale 13

TRANSMITEREA CARACTERELOR PATOLOGICE LA OMCaracterele patologice umane sunt, in cea mai mare parte, monogenice si se transmit dupa modelul mendelian. Ereditatea autozomala X-linkata Y-linkata(holandrica) Transmiterea autozomal dominanta Transmiterea autozomal recesiva Transmiterea legata de cromozomul sexual : - recesiva X-linkata dominanta X-linkata holandrica (legata de cromozomul Y)

Unaffected Carrier Father

Unaffected Carrier Mother

R R R

r r R R

R r

r r r

Unaffected 1 in 4 chance

Carrier Unaffected 1 in 4 chance

Carrier Unaffected 1 in 4 chance

Affected 1 in 4 chance

Unaffected Father

Usually Unaffected Carrier Mother

X

Y

X

X

X

X

X

Y

X

X

X

Y