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Different Patterns of Inheritance. Blood Types, Sex-Linked and Polygenic Traits. Blood Typing!. 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. - PowerPoint PPT Presentation
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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+ blood AB-, AB+, A-, A+, B-, B+, O-, O+ blood
O- blood O- blood
O+ blood O-, O+ blood
Blood Type Crosses!
Samara is type ABNaveen is type A
his 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 BKyle 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