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Patterns of Inheritance

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

1 Patterns of Inheritance

2 Pedigrees Visually displays inheritance patterns across a family tree
Useful for tracing the inheritance patterns of disease and other genetic abnormalities Autosome: A non-sex chromosome, equal number of copies of these chromosomes in males an females 22 autosomal pairs in humans + 1 pair sex chromosomes

3 Pedigree Basics Females represented by circles
Males represented by square Unaffected or Carrier Affected Unaffected or Carrier Affected

4 Pedigree Basics Horizontal lines connect parents
Vertical lines denote descendants of parents All offspring of the same parents are connected by horizontal lines Parents Offspring

5 Pedigree Basics Individuals are numbered left to right starting from the first line and continue down the whole pedigree 1 2 1 3 4 5 6 7

6 Analyzing a Pedigree Autosomal Dominant Inheritance
Trait usually does not skip generations An affected person married to an unaffected person should have approximately 50% of the offspring being affected. Affected individual is heterozygous for the trait Distribution of the trait should be close to equal distribution among the sexes.

7 Pedigree of autosomal dominant trait

8 Analyzing a Pedigree Autosomal Recessive Inheritance
Trait can skip generations. Distribution of the trait should be close to equal distribution among the sexes. Traits are often found in pedigrees with consanguineous marriages (Marriage among close relatives). If both of the parents are affected, all of the children should be affected. Most affected individuals have "normal" parents who were carriers. When an unaffected person is married to an affected individual, all of the children are normal The normal parent is homozygous dominant If a heterozygous carrier is married to an affected individual, then approximately half of the children should be affected. Showing that the "normal" parent is heterozygous

9 Pedigree of autosomal recessive trait
Homozygous recessive individual are unlikely live to reproductive age. Typically, occurrences of the condition will be in matings between two heterozygotes (or carriers) ¼ chance that any child will be affected

10 Carriers Carriers of a trait will not express the trait but their offspring may exhibit the trait

11 Blood Types Important to know blood type because giving someone the wrong blood type leads to severe complications and death Individuals carry antibodies to non-self blood types

12 Blood Types Basic rules: Type A : AA or AO Type B: BB or BO Type O: OO
Antibodies against type B Type B: BB or BO Antibodies against type A Type O: OO Universal donor, no antigens Type AB: AB Universal acceptor, no antibodies


14 Lab Exam Lab exam 2 Next Week
Know everything that is on the study guide

15 Exam 2 Review Punnet squares Cell cycle lab Pedigrees
Know the phases of mitosis and be able to calculate time spent in each cell cycle (remember, 16 hours is not a constant!) Punnet squares Know how to analyze genetic crosses Know how to calculate genotypic and phenotypic ratios, percentages, etc… Pedigrees Be able to draw and analyze a pedigree

16 Exam 2 Material PCR Understand what is happening in the reaction
Know what each reagent does and what role each plays in the reaction Know the rules of primer design, and be able to make both forward and reverse primers Know what is happening and the temperatures during denaturation, annealing, and elongation.

17 TA Evaluations

18 Next Lab Exercise 6 on pedigrees due Lab quiz 2
If you are taking BSC 196 DO NOT SELL BACK YOUR TEXTBOOKS! You will use the same textbook that you used for this class.

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