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Pedigree Charts The family tree of genetics I II III.

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Presentation on theme: "Pedigree Charts The family tree of genetics I II III."— Presentation transcript:


2 Pedigree Charts The family tree of genetics I II III

3 Overview I. What is a pedigree? a. Definition b. Uses II. Constructing a pedigree a. Symbols b. Connecting the symbols III. Interpreting a pedigree

4 Pedigree definition  Pedigree: a family history that shows how a trait is inherited over several generations  Pedigrees are usually used when parents want to know if they are carriers of a particular disorder

5 Making a Pedigree  Female  Male  Married Couple  Siblings Filled in symbols indicate individual is affected with a disorder

6 Connecting Pedigree Symbols  Fraternal twins  Identical twins Examples of connected symbols:

7 Example of a Pedigree You Parents Aunts, Uncles Grandparents Brother Do any disorders run in this family??

8 Example of Pedigree Charts  How is the disorder most likely inherited? Autosomal recessive.

9 Answer  Recessive

10 Example of Pedigree Charts How is the disorder most likely inherited? Autosomal dominant: The trait runs in every generation and affects several family members.

11 You Parents Aunts, Uncles Grandparents Brother Sex Linked! The allele is inherited on the x chromosome

12 Interpreting a Pedigree Chart 1. Determine if the pedigree chart shows an autosomal or X-linked disease. –If most of the affected individuals in the pedigree are male the disorder is X- linked –If there is more of a balance between the ratio of the men and women the disorder is autosomal.

13 Interpreting a Pedigree Chart 2. Determine whether the disorder is dominant or recessive. –If the disorder is dominant, one of the parents must have the disorder. –If the disorder is recessive, neither parent has to have the disorder because they can be heterozygous.

14 Summary  Pedigrees are family trees that explain your genetic history.  Pedigrees are used to find out the probability of a child having a disorder in a particular family.  To begin to interpret a pedigree, determine if the disease or condition is autosomal or X-linked and dominant or recessive.

15 Pedigree Chart -Cystic Fibrosis

16 Human Genetics

17 Karyotype

18 Chromosome Number  Different # for different species  Full set = 2N=Diploid  N=  # pairs  1 pair from mother  1 pair from father  Humans= 23 pairs or  46 total Homologous Chromosomes are the sets of each pair

19 Autosomes & Sex Chromosomes Autosomes = # 1- 22 for all traits except sex Sex chromosomes= Pair # 23 XX(female) or XY(male)

20 Down Syndrome= 3 of #21

21 Klinefelter’s = XXY

22 Multiple Alleles  More than one type of allele for a trait  Example: Blood Type  TYPES: A I A I A, I A i B I B I B, I B i AB I A I B O ii

23 Mutation  Change in DNA code  Caused by: 1. Chemical damage 2. Errors in Replication 3. X-ray damage 4. UV damage A T GCGC A to A G C

24 Mutation  Changes in the DNA code  = Changes in the final proteins made  =Changes in the organism

25 Genetic Technology  Recombinant DNA &  Bacterial Transformation

26 1. Transgenic tobacco plant?  Genetically engineered  Inserting fire fly genes into the plant  Using “cut & paste” enzymes

27 2. Genetic Engineering:  Altering the genetic makeup of an organism  By Cutting DNA from one organism and inserting fragments into a host  Recombinant DNA  Alters the allele frequency of a population by artificial means

28 Recombinant DNA:  “Recombine”  Connecting or reconnecting DNA fragments  DNA of two different organisms  Example: lab of inserting human DNA into bacteria

29 Genetic Engineering of Insulin Human DNA cut out Human DNA put into bacteria DNA Bacteria DNA is opened up Many Bacteria Grow human insulin

30 4. Transgenic Organism:  “trans” = across  “genic” = race  Contains genes from another organism  Bacteria  Virus  Human

31 5. Tobacco Recombinant DNA Process: a. Isolated DNA to be inserted into host b. Attach DNA fragment to a vehicle (vector) c. Transfer the vector to the host= Transgenic organisms

32 Restriction Enzymes: Restriction Enzymes cut DNA at very specific sites Separate the base pairs of both strands “ Scissors ” in Recombinant DNA Human Cut Bacterium DNA cut

33 7. “Sticky ends”  DNA cuts that have single stranded ends  Attract corresponding base pairs  Made by special restriction (cutting) enzymes GGCC ATTAC CCGC TACCGG TAAT GATGGC Stick together

34 Vectors = vehicles  Carry foreign DNA fragments into the host  Bacteria carried the firefly DNA into the tobacco cells  Biological or  Mechanical

35 Vectors: Biological:  Virus  Bacterial plasmid (circular DNA) Mechanical:  Micropipett e  Metal bullet coated with DNA

36 Recombinant DNA Uses:  Grow human hormones in bacteria cultures  Artificial sweeteners using bacteria to make amino acids  Study human diseases by inserting human DNA into mice  Replace incorrect DNA sequences  Replace harmful bacteria on plants  Nitrogen bacteria in the soil & plants to make fertilizer  Improve transport of fruits  Resist diseases  Increase protein production

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