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Different Patterns of Inheritance

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Presentation on theme: "Different Patterns of Inheritance"— Presentation transcript:

1 Different Patterns of Inheritance
Blood Types, Sex-Linked and Polygenic Traits

2 Blood Typing! Phenotype Genotype A AA or AO B BB or BO AB O OO

3 AB-, AB+, A-, A+, B-, B+, O-, O+ blood
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-, O+ blood

4 Blood Type Crosses! Samara is type AB Naveen 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 O OO S= AB N = AO 50% A 25% AB 25% B

5 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 O OO

6 Polygenics Multiple GENES affect the traits being expressed Skin color
Hair color Eye color

7 How it works… Eye Color = Hazel Eye Color = Brown Skin Color = Tan
Skin Color = Light

8 Eye Color

9 Sex Linked Traits Sex Chromosomes (X, Y)
In humans male determined sex of offspring Give X = female Give y= male Genes can be located on sex chromosomes = Sex Linked Traits Mostly on X for humans

10 Fly Experiment 100% 50% 0% 50% Eye color carried on X
R = red r = white More males are white than female because.. SEX LINKED TRAIT!! (only on X Chromosome) Male XY Female XX 100% % 0% %

11 Sex Linked Disease 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

12 Sex-Linked Genetic Cross
No Traits carried on “Y” This is why MALES usually show the recessive trait!!

13 Reinforcement Pg ( 3 P.R.) Pg (3 P.R.)

14 A family history of a genetic condition
PEDIGREE CHARTS A family history of a genetic condition

15 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.

16 Studying Human Genetics
Pedigree charts offer an ethical 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 disease in an affected family

17 Symbols used in pedigree charts
A marriage with five children, two daughters and three sons. The second born son is affected by the condition. Eldest child  Youngest child Normal male Affected male Normal female Affected female Marriage

18 Organising the pedigree chart
A pedigree chart of a family showing 20 individuals

19 Organising the pedigree chart
Generations are identified by Roman numerals I II III IV

20 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

21 Different Patterns of Inheritance
Sex-Linked Recessive Passed on the X or Y chromosome Usually X What this means… Girls can be carriers (XX) Males either have it or are normal (XY) Examples: Hemophilia, color-blindness, muscular dystrophy

22 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 copy from both parents. expressed in males if present Possible Carriers in females Shown by half filled circles Usually more males show this!! Cannot have sick male, normal mother

23 Autosomal Dominant All unaffected individuals are homozygous for the normal recessive allele.

24 Autosomal Recessive All affected are homozygous.
Incest matings are often (but not always) involved. Heterozygous are “normal”

25 Dominant vs. Recessive Autosomal
Is it a dominant pedigree or a recessive pedigree? 1. If two affected people have an unaffected child, it must be a dominant pedigree 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 recessive 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 dominant pedigree.

26 Dominant Autosomal Pedigree
1. If two affected people have an unaffected child, it must be a dominant pedigree 1 2 3 4 5 6 7 8 9 10 I II III

27 Recessive Autosomal Pedigree
If two unaffected people have an affected child, it is a recessive pedigree

28 Recessive Sex Linked Pedigree
If I don’t tell you.. Look for shading If I tell you, shade it

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