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Different Patterns of Inheritance

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.

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Different Patterns of Inheritance

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

  2. Blood Typing!

  3. Blood Types • Type O-negative blooddoes not have any antigens. • It is called the "universal donor" type because it is compatible with any blood type. • Type AB-positive bloodis called the"universal recipient"type because a person who has it can receive blood of any type. + = have Rh protein - = no Rh protein

  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? 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?

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

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

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

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

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

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

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

  20. 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

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

  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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