5.2 Inheritance

5.2 INHERITANCE Inheritance of Traits in Humans

Determination of blood group • The ABO blood group system is based on

presence or absence presence or absence of  of antigens A & B • The antigens is controlled by alleles A, A, B & O Allele

A: produce antigen A Allele B: produce B: produce antigen B Allele O: does O: does not produce any antigens

Eample !

Eample "

EXERCISE

• A  A man #ith blood blood group group O marries marries

a #oman #ith blood group B$ • Eplain #ith a genetic diagram, ho#

is it possible for the couple to ha%e a child #ith blood group O • 'hat is the percentage of their first child ha%ing blood B

(HE)*) (HE )*) +ATO(

(hesus +actor -(h +actor. • (eferring to the antigen  found on the antigen found

surface membrane of some red bld cells • R!es"s psiti#e $R! %  • /eople #ho ha%e (hesus factor 

• R!es"s negati#e $R! ' • /eople #ho do not ha%e

• Allele for r!es"s % is d(inant t r!es"s '

+ather  (hesus positi%e (h 0 (h 1

(h 0

2other  (hesus negati%e (h 3 (h 1

4

(h 1

(h 1

(h 1

2ale gamete +emale gamete

(h 0

(h 1

(h 1

(h 0 (h 1

(h1 (h1

(h 1

(h0 (h1

(h1 (h1

(h0 (h1 (hes (h esus us po posi siti ti%e %e !

5 (h1 (h1 5 (h (hes esus us ne nega gati ti%e %e 5!

(hesus factor & /regnancies )t!er*s R! +actr 

,at!er*s R! +actr 

BabBa b-**s R! R! +a +act ctr r

re r eca ca"t "ti ins ns

(h 0

(h 0

(h 0

6one

(h 1

(h 1

(h 1

6one

(h 0

(h 1

ould be (h 0 or (h 1

6one

(h 1

(h 0

ould be (h positi%e or (h negati%e

(h immune globulin in7ections

*6DE()TA6DI68 I6HE(ITA6E Determination of the se of a child

hromosomes • T# T#o o types of

chromosomes5 •  Autosomes • )e chromosomes

SEX

A/TOSO)ES

SEX SO)ATIC CE00 CHRO)OSO)ES

2ale

99 : "" pairs

4;

99 0 4;

,e(ale

99 : "" pairs

44

11 % XX

DETE(2I6ATIO6 O+ THE )E4 O+ A HI HI