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Pedigree Charts The family tree of genetics Pedigree Charts I II III.

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


2 Pedigree Charts The family tree of genetics

3 Pedigree Charts I II III

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

5 What is a Pedigree?  A pedigree is a chart of the genetic history of family over several generations.  Scientists or a genetic counselor would find out about your family history and make this chart to analyze.

6 Constructing a Pedigree  Male  Female

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

8 Connecting Pedigree Symbols  Married Couple  Siblings Examples of connected symbols:

9 Example  What does a pedigree chart look like?

10 Symbols in a Pedigree Chart  Affected  X-linked  Autosomal carrier  Deceased

11 Interpreting a Pedigree Chart 1. Determine if the pedigree chart shows an autosomal or X-linked disease. –If most of the males in the pedigree are affected the disorder is X-linked –If it is a 50/50 ratio between men and women the disorder is autosomal.

12 Example of Pedigree Charts  Is it Autosomal or X-linked?

13 Answer  Autosomal

14 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.

15 Example of Pedigree Charts  Dominant or Recessive?

16 Answer  Dominant

17 Example of Pedigree Charts  Dominant or Recessive?

18 Answer  Recessive r1t9awmUl4

19 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.

20 Pedigree Chart -Cystic Fibrosis

21 Human Genetics

22 Karyotype

23 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

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

25 Down Syndrome= 3 of #21

26 Klinefelter’s = XXY

27 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

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

29 Mutations  Chromosome mutations involve changes in the structure of a chromosome or the loss or gain of a chromosome.  There are three types of chromosome mutations:  1. deletion: the loss of a piece of a chromosome due to breakage.  2. inversion: a chromosomal segment breaks off, flips around backward and then re-attaches.  3. translocation: a piece of one chromosome breaks off and re attaches to a non-homologous chromosome.


31 Genetic Technology  Recombinant DNA &  Bacterial Transformation

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

33 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

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

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

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

37 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

38 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

39 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

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

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

42 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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