Introduction to Genetics. It all started here The Beginnings of genetics Genetics - is the study of heredity or the study of passing of traits from parent

Introduction to Genetics

It all started here

The Beginnings of genetics

Genetics - is the study of heredity

or the study of passing of traits from parent to offspring

* The father was Gregor Mendel

Questions:

Who is the father of genetics?

What is genetics?

HE.912.C.1.4 Analyze how heredity and family history impact health

What was known? Chromosomes determine

everything about living things Come in pairs During meiosis they segregate to

make a gamete (egg or sperm) Fertilization - pairs the

chromosomes again The 2 types are autosomes and

sex chromosomes

Questions:Explain the types of

chromosomes and their importance.

What is the importance of meiosis?

Why is fertilization important?

SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.17 Compare mitosis and meiosis and relate to the process of sexual and asexual reproduction and their consequences for genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health

When fertilization occurs … Each parent gives one of each pair of chromosomes

Importance of segregation

Without segregation an offspring will not get the correct number of chromosomes – resulting in mutations or deathToo many is called polyploidy

Example: Down syndrome - extra 21st chromosome

Questions:

What is segregation and why is it so important?

SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritanceSC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health

Extra 21

Extra 13

Mendel’s Discoveries On chromosome are genes

They determine a specific trait

Gene have different forms called alleles Dominant alleles - strong

(shown with a capital letter) Recessive alleles - weaker

(shown with a lower case letter)

Questions:

What is the difference between a gene and allele?

What 2 forms can alleles take?

SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.HE.912.C.1.4 Analyze how heredity and family history impact health

Importance of alleles Typically there are 2 alleles

that represent each traitThis two letter combination

is called the genotype TT or Tt or tt

We use the genotype to determine what it looks like – called the phenotype

Questions:

What is the difference between the genotype and phenotype?

SC.912.L.16.2 Discuss observed inheritance patterns caused by various modes of inheritance, including dominant, recessive, codominant, sex-linked, polygenic, and multiple alleles.SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.

Determining what the trait looks like

Dominant traits - are always seen RR and Rr both will show the

dominant trait

Recessive traits – only seen if there are no dominants present rr will show the recessive trait

Questions:

What is the difference between a dominant and recessive trait?



Codominance - both traits are seen Example:

multicolored shells or cats


Incomplete dominance – none are dominant so they mixExample: red flower plus

white flower = pink flower

Questions:

What is the difference between codominance and incomplete dominance?



Multiple alleles – when there are more than 2 alleles that control the trait But still only 2 letters in the

genotype Blood type has A B and O

A blood type: XAXA or XAXO

B blood type: XBXB or XBXO

AB blood type: XAXB

O blood type: XOXO

Questions:

Explain what multiple alleles means and explain an example.



Polygenic traits – have more than 2 genes for a trait that all effect the outcome The genotype has more

than 2 letters (AAbbCc)Example - skin color, hair

color, height

Questions:

What is a polygenic trait and why does it allow for so much diversity?



Determining the possibilities Probability – is the likelihood

an event will occur In genetics the Punnett

square is diagram used to determine the genetic probability of an offspring

It tells you what the parents have, what the children could have, but it never tells you the actual outcome

Questions:

What is probability and how is it used in determining the possible genetic outcomes?

SC.912.L.15.15 Describe how mutations and genetic recombination increase genetic variation.

Using the Punnett Square First - determine the

genotypes both parentsHomozygous dominant -

both letters are capitalHomozygous recessive -

both letters are lower caseHeterozygous - one letter

is capital and the other is lower case

Questions:What is the

difference between homozygous and heterozygous?

Why do you need to know the parent genotypes first?

SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.

Step 2: Fill in the square

If B=brown eyes and b=blue eyesCross a homozygous dominant and a homozygous recessive individual

B B

b

b

Bb Bb

Bb Bb


Interpreting the Punnett Square

RatiosGo from most dominant to

most recessive Include genotypic ratios Include phenotypic ratios

Questions:

How do you find ratios and percentages for the Punnett square?


What if we look at more than one trait?

Follow the Principle of independent assortment – says that genes for different traits segregate independently In other words – each parent will

give one of each letter to the offspring

Example: RrYy Possibilities alleles passed are

RY Ry rY ry

Questions:

What does the principle of independent assortment state?

Why is this idea important?

SC.912.L.16.1 Use Mendel’s laws of segregation and independent assortment to analyze patterns of inheritance.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.

Genetic disorders Dominant disorders – on

the dominant genes All it takes is one bad gene

and you have itExample: Achondroplasion -

dwarfism

Questions:

What is a dominant disorder and why is it so dangerous?

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.HE.912.C.1.4 Analyze how heredity and family history impact health

Dwarfism

Primordial Dwarfism

Genetic disorders Recessive disorders – are

on the recessive alleles If you have 2 recessive you

have it If you have 1 you are a

carrierExample:

Cystic Fibrosis – mucus in lungs

Albinism – no melanin

Questions:

What are recessive disorders?

Why is being a carrier still dangerous?


Albinism

Genetic disorders Sex linked disorders – on the

X and Y chromosomes If it is on the X

Females – both parent must give it Males – only mom gives it

If it is on the y Females – don’t get because no y Males – if dad has it all sons have it

Examples on X: Baldness – loosing hair Hemophilia – blood can’t clot properly

Questions:

Why is it more dangerous for boys than girls when it comes to sex linked disorders?


Baldness

Color Blindness

http://www.kcl.ac.uk/teares/gktvc/vc/lt/colourblindness/cblind.htm

http://webexhibits.org/causesofcolor/2.html#vissamp

Genes affected by the environment

Characteristics can be affected by the environmentExamples:

Nutrition affects height Scholastic verses non-

scholastic home affect intelligence

Questions:

How can environmental factors affect characteristics?

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.

Why organisms naturally different

Crossing over Independendant

assortment Mutations

Questions:

Explain organisms naturally differ?


How humans cause variations? Mutations – environmental or

chemical Hybridization – crossing 2 dissimilar

organisms Selective breeding – crossing 2 of

same species Inbreeding – crossing organisms in

the same family tree Genetic engineering - the process of

man reading, editing, and reinserting pieces of DNA

Questions:

Explain how man has caused genetic difference in organisms.

SC.912.L.14.6 Explain the significance of genetic factors, environmental factors, and pathogenic agents to health from the perspectives of both the individual and public health.SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including medical and ethical issues.

1. Extract DNA2. Read the Sequence3. Cutting the DNA4. Separating DNA – using electrophoresis 5. Pasting – using enzymes6. Making Copies

Cell Transformation in Bacteria Cell transformation - process of

taking DNA from one cell into another cell

They use bacteria Foreign DNA is joined to a

circular DNA called a plasmid Plasmid is mixed with bacteria Treated with anti-bacteria to

kill all cell except those with the new gene

Questions:

Explain how man has caused genetic difference in organisms.

SC.912.L.15.15 Describe how mutations and genetic recombination increases genetic variations.SC.912.L.16.10 Evaluate the impact of biotechnology on the individual, society, and the environment, including medical and ethical issues.

Using Bacteria For Genetic Engineering

Documents

Introduction to Genetics. It all started here The Beginnings of genetics Genetics - is the study of heredity or the study of passing of traits from parent