Pedigree ChartsPedigree ChartsThe family tree of geneticsThe family tree of genetics

I

II

III

OverviewOverview

I.I. What is a pedigree? What is a pedigree? a.a. DefinitionDefinition

b.b. UsesUses

II.II. Constructing a pedigree Constructing a pedigree a.a. SymbolsSymbols

b.b. Connecting the symbolsConnecting the symbols

III.III. Interpreting a pedigree Interpreting a pedigree

Pedigree definitionPedigree definition

Pedigree: a family history that shows Pedigree: a family history that shows how a trait is inherited over several how a trait is inherited over several generationsgenerations

Pedigrees are usually used when Pedigrees are usually used when parents want to know if they are parents want to know if they are carriers of a particular disordercarriers of a particular disorder

Making a PedigreeMaking a Pedigree

FemaleFemale

MaleMale

Married CoupleMarried Couple

SiblingsSiblings

Filled in symbols indicate individual is affected with a disorder

Connecting Pedigree SymbolsConnecting Pedigree Symbols

Fraternal twinsFraternal twins

Identical twinsIdentical twins

Examples of connected symbols:Examples of connected symbols:

Example of a PedigreeExample of a Pedigree

You

Parents

Aunts, UnclesAunts, Uncles

GrandparentsGrandparents

BrotherDo any disorders run in this family??

Example of Pedigree ChartsExample of Pedigree Charts How is the disorder most likely How is the disorder most likely

inherited?inherited?

Autosomal recessive.

AnswerAnswer

RecessiveRecessive

Example of Pedigree ChartsExample of Pedigree Charts

How is the disorder most likely How is the disorder most likely inherited?inherited?

Autosomal dominant: The trait runs in every generation and affects several family members.

You

Parents

Aunts, UnclesAunts, Uncles

GrandparentsGrandparents

Brother

Sex Linked! The allele is inherited on the x chromosome

Interpreting a Pedigree ChartInterpreting a Pedigree Chart

1.1. Determine if the pedigree chart shows an Determine if the pedigree chart shows an autosomal or X-linked disease.autosomal or X-linked disease.

– If most of the affected individuals in the If most of the affected individuals in the pedigree are male the disorder is X-linked pedigree are male the disorder is X-linked

– If there is more of a balance between the If there is more of a balance between the ratio of the men and women the disorder ratio of the men and women the disorder is autosomal.is autosomal.

Interpreting a Pedigree ChartInterpreting a Pedigree Chart

2.2. Determine whether the disorder is Determine whether the disorder is dominant or recessive.dominant or recessive.

– If the disorder is dominant, one of If the disorder is dominant, one of the parents must have the disorder.the parents must have the disorder.

– If the disorder is recessive, neither If the disorder is recessive, neither parent has to have the disorder parent has to have the disorder because they can be heterozygous.because they can be heterozygous.

SummarySummary

Pedigrees are family trees that Pedigrees are family trees that explain your genetic history.explain your genetic history.

Pedigrees are used to find out the Pedigrees are used to find out the probability of a child having a probability of a child having a disorder in a particular family.disorder in a particular family.

To begin to interpret a pedigree, To begin to interpret a pedigree, determine if the disease or condition determine if the disease or condition is autosomal or X-linked and is autosomal or X-linked and dominant or recessive.dominant or recessive.

Pedigree Chart -Cystic FibrosisPedigree Chart -Cystic Fibrosis

Human GeneticsHuman Genetics

KaryotypeKaryotype

Chromosome NumberChromosome Number

Different # for Different # for different speciesdifferent species

Full setFull set = = 2N=2N=DiploidDiploid

N=N= # pairs# pairs 1 pair from mother1 pair from mother 1 pair from father1 pair from father Humans= Humans= 23 pairs23 pairs or or 46 total46 total

Homologous Chromosomes are the sets of each pair

Autosomes & Sex Autosomes & Sex ChromosomesChromosomes

Autosomes = # 1-22 for all traits except sex

Sex chromosomes= Pair # 23 XX(female) orXY(male)

Down Syndrome= 3 of #21Down Syndrome= 3 of #21

KlinefelterKlinefelter’’s = XXYs = XXY

Multiple AllelesMultiple AllelesMore than More than one type one type of allele of allele for a traitfor a trait

Example:Example:

Blood TypeBlood Type

TYPES:TYPES:

A A IIAAIIAA, I, IAAii

B B IIBBIIB B , I, IBBii

AB AB IIAAIIBB

O O iiii

MutationMutation ChangeChange in DNA in DNA

codecode Caused by:Caused by:

1.1. Chemical Chemical damagedamage

2.2. Errors in Errors in ReplicationReplication

3.3. X-ray damageX-ray damage

4.4. UV damageUV damage

ATGC

Ato A G C

MutationMutationChanges in the Changes in the

DNA code DNA code = Changes in = Changes in

the final the final proteins madeproteins made

=Changes in =Changes in the organismthe organism

Genetic Genetic TechnologyTechnology

Recombinant DNA &Recombinant DNA &Bacterial TransformationBacterial Transformation

1. Transgenic tobacco plant?1. Transgenic tobacco plant?

Genetically Genetically engineeredengineered

Inserting fire Inserting fire fly genes fly genes into the into the plantplant

Using Using ““cut & cut & pastepaste”” enzymesenzymes

2. Genetic Engineering:2. Genetic Engineering:

Altering the genetic makeup Altering the genetic makeup of an organismof an organism

By Cutting DNA from one By Cutting DNA from one organism and inserting organism and inserting fragments into a hostfragments into a host

Recombinant DNARecombinant DNAAlters the allele frequency of Alters the allele frequency of

a population by artificial a population by artificial meansmeans

Recombinant DNA:Recombinant DNA:

““RecombineRecombine””Connecting or Connecting or

reconnecting DNA reconnecting DNA fragmentsfragments

DNA of two different DNA of two different organismsorganisms

Example: lab of inserting human DNA Example: lab of inserting human DNA into bacteriainto bacteria

Genetic Engineering of InsulinGenetic Engineering of InsulinHuman DNA cut out

Human DNA put into bacteria DNA

Bacteria DNA is opened up Many BacteriaGrow humaninsulin

4. Transgenic Organism:4. Transgenic Organism:““transtrans”” = across = across““genicgenic”” = race = raceContains genes from Contains genes from

another organismanother organismBacteriaBacteriaVirusVirusHumanHuman

5. Tobacco Recombinant DNA 5. Tobacco Recombinant DNA Process:Process:

a.a. Isolated DNA to be Isolated DNA to be inserted into hostinserted into host

b.b. Attach DNA fragment to a Attach DNA fragment to a vehicle (vector)vehicle (vector)

c.c. Transfer the vector to the Transfer the vector to the host=host=

Transgenic organismsTransgenic organisms

Restriction Enzymes: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

7. 7. ““Sticky endsSticky ends””DNA cuts that have DNA cuts that have singlesingle

stranded endsstranded endsAttract corresponding base Attract corresponding base

pairspairsMade by special restriction Made by special restriction

(cutting) enzymes(cutting) enzymes

GGCCATTACCCGC TACCGG

TAATGATGGCStick together

Vectors = vehiclesVectors = vehiclesCarry foreign DNA Carry foreign DNA fragments into the hostfragments into the host

Bacteria carried the firefly Bacteria carried the firefly DNA into the tobacco cellsDNA into the tobacco cells

Biological orBiological orMechanicalMechanical

Vectors:Vectors:

Biological:Biological:VirusVirusBacterial Bacterial plasmid plasmid (circular (circular DNA)DNA)

Mechanical:Mechanical:MicropipettMicropipettee

Metal bullet Metal bullet coated with coated with DNADNA

Recombinant DNA Uses:Recombinant DNA Uses: Grow human Grow human

hormones in hormones in bacteria culturesbacteria cultures

Artificial Artificial sweeteners using sweeteners using bacteria to make bacteria to make amino acidsamino acids

Study human Study human diseases by diseases by inserting human inserting human DNA into miceDNA into mice

Replace incorrect Replace incorrect DNA sequencesDNA sequences

Replace harmful Replace harmful bacteria on bacteria on plantsplants

Nitrogen bacteria Nitrogen bacteria in the soil & in the soil & plants to make plants to make fertilizerfertilizer

Improve Improve transport of fruitstransport of fruits

Resist diseasesResist diseases Increase protein Increase protein

productionproduction