Different Different Patterns of Patterns of InheritanceInheritance

Blood Types, Sex-Linked Blood Types, Sex-Linked and Polygenicand Polygenic

TraitsTraits

Blood Typing!Phenotype Genotype

A AA or AO

B BB or BO

AB AB

O OO

Blood Types

Type O-negative blood does not have any antigens. It is called the

"universal donor" type because it is compatible with any blood type.

Type AB-positive blood is called the "universal recipient" type because a person who has it can receive blood of any type. + = have Rh protein- = no Rh protein

A person who has:

Can receive:

A- blood A-, O- blood

A+ blood A-, A+, O-, O+ blood

B- blood B-, O- blood

B+ blood B-, B+, O-, O+ blood

AB- blood AB-, O- blood

AB+ bloodAB-, AB+, A-, A+, B-, B+, O-, O+

blood

O- blood O- blood

O+ blood O-, O+ blood

Blood Type Crosses!

Samara is type AB

Naveen is type Ahis mother was A, Father O

What are their genotypes?

What are their possible offspring’s blood types?

Phenotype

Genotype

A AA or AO

B BB or BO

AB AB

O OO

S= AB N = AO

50% A25% AB25% B

Blood Typing!

Kristina is type B

Kyle is type A

Is is possible for their child to be type O?

Phenotype

Genotype

A AA or AO

B BB or BO

AB AB

O OO

PolygenicsPolygenicsMultiple GENES affect the traits being expressed

Skin colorHair colorEye color

How it works…

Eye Color = Brown

Skin Color = Light

Eye Color = Hazel

Skin Color = Tan

Eye Color

Sex Linked TraitsSex Linked Traits

Sex Chromosomes (X, Y)Sex Chromosomes (X, Y) In humans male determined sex of offspringIn humans male determined sex of offspring

• Give X = femaleGive X = female• Give y= maleGive y= male

Genes can be located on sex chromosomes = Sex Linked TraitsMostly on X for humans

Fly ExperimentFly Experiment

Eye color carried on X R = red r = white More males are white than female

because..

SEX LINKED TRAIT!! SEX LINKED TRAIT!!

(only on X Chromosome)(only on X Chromosome)

Male XY Female XX

100% 50%

0% 50%

Sex Linked Sex Linked DiseaseDisease

Females can be carriers, males will show it Red- green color blindness Night Blindness Fragile X syndrome Sickle Cell Anemia Huntington's disease Cystic Fibrosis Hemophilia

Sex-Linked Genetic Cross

No Traits

carried on “Y”

This is why MALES

usually show the

recessive trait!!

Reinforcement

Pg 175- 176 ( 3 P.R.) Pg 180-182 (3 P.R.)

PEDIGREE CHARTS

A family history of a genetic condition

What is a pedigree chart?

Pedigree charts show a record of the family of an

individual They can be used to study the transmission of a

hereditary condition They are particularly useful when there are large

families and a good family record over several

generations.

Studying Human Genetics

Pedigree charts offer an ethicalethical way of studying human genetics

Today genetic engineering has new tools to offer doctors studying genetic diseases

A genetic counsellor will still use pedigree charts to help determine the distribution of a diseasedistribution of a disease in an affected family

Symbols used in pedigree charts

Normal male Affected male Normal female Affected female Marriage

A marriage with five children, two daughters and three sons. The second born son is affected by the condition.

Eldest child Youngest child

Organising the pedigree chart

A pedigree chart of a family showing 20 individuals

Organising the pedigree chart

Generations are identified by Roman numerals

I

II

III

IV

Organising the pedigree chart

Individuals in each generation are identified by Roman numerals numbered from the left

Therefore the affected individuals are II3, IV2 and IV3

I

II

III

IV

Different Patterns of Inheritance Sex-Linked RecessiveSex-Linked Recessive

Passed on the X or Y chromosome •Usually XUsually X

What this means…•Girls can be carriers (XX)Girls can be carriers (XX)•Males either have it or are normal Males either have it or are normal (XY)(XY)

•Examples:• Hemophilia, color-blindness, muscular Hemophilia, color-blindness, muscular

dystrophydystrophy

Sex-Linked Recessive

males get their X from their mother

fathers pass their X to daughters only

females express it only if they get a females express it only if they get a copy from both parents.copy from both parents.

expressed in males if present

Possible Carriers in females Shown by half filled circlesShown by half filled circles

Usually more males show this!!Usually more males show this!! Cannot have sick male, normal Cannot have sick male, normal

mothermother

Autosomal Autosomal DominantDominant

All unaffected individuals are homozygous for the normal recessive allele.

Autosomal Autosomal RecessiveRecessive

All affected are homozygous.

Incest matings are often (but not always) involved.

Heterozygous are “normal”

Dominant vs. Recessive Dominant vs. Recessive AutosomalAutosomal

Is it a dominant pedigree or a recessive pedigree?

1. If two affected people have an unaffected child, it must be a dominant If two affected people have an unaffected child, it must be a dominant pedigreepedigree D is the dominant mutant allele and d is the recessive wild type allele. Both

parents are Dd and the normal child is dd. 2. If two unaffected people have an affected child, it is a If two unaffected people have an affected child, it is a

recessive pedigreerecessive pedigree: R is the dominant wild type allele and r is the recessive mutant

allele. Both parents are Rr and the affected child is rr. 3. If every affected person has an affected parent it is a If every affected person has an affected parent it is a

dominant pedigreedominant pedigree..

1 2 3 4 5 6 7 8 9 10

1 2

I

1 2 3 4 5 6

II

III

Dominant Autosomal Dominant Autosomal PedigreePedigree

1. If two affected people have If two affected people have an unaffected child, it must be an unaffected child, it must be a dominant pedigreea dominant pedigree

Recessive Recessive Autosomal PedigreeAutosomal Pedigree

If two unaffected If two unaffected people have an people have an affected child, it affected child, it is a recessive is a recessive pedigreepedigree

Recessive Sex Linked Recessive Sex Linked PedigreePedigree

If I don’t tell you.. Look for If I don’t tell you.. Look for shadingshading

If I tell you, shade itIf I tell you, shade it