http://www.youtube.com/watch?v=ToAozF30e9g

Bell Ringer #1Think about your family for a moment. What physical characteristics or traits do you share with your family members?

What personality characteristics do you share with some of your family members?

Introduction to Genetics for beginners

An Introduction to basic genetic concepts and links to health for individuals who have had minimal experience of

genetics

DNA, genes & chromosomes

The objectives of this presentation are to:Understand the role and structure of DNA, genes

and chromosomes.Understand that proteins are encoded by genesBe aware that alterations in genetic material can

cause disease

The structure of DNA, genes & chromosomes

Genes are a set of coded instructions that code for a specific trait!

Chromosomes

• Chromosomes are made of DNA. • Each contains genes in a linear

order.• Human body cells contain 46

chromosomes in 23 pairs – one of each pair inherited from each parent

• Chromosome pairs 1 – 22 are called autosomes.

• The 23rd pair are called sex chromosomes: XX is female, XY is male.

Gene for sickle cell disease (chromosome 11)

Gene for cystic fibrosis (chromosome 7)

Chromosomes

p

Centromere

q

Chromosome 5

The Karyotype

A normal male chromosome pattern would be described as:

46,XY.

46 = total number of chromosomesXY = sex chromosome constitution

(XY = male, XX = female).

Any further description would refer to any abnormalities orvariants found

Total Genes On Chromosome: 723373 genes in region marked red, 20 are shown

FZD2AKAP10ITGB4KRTHA8WD1SOST

MPP3

MLLT6

STAT3

BRCA1breast cancer 1, early onsetGFAPNRXN4NSF

NGFR

CACNB1HOXB9HTLVRABCA5CDC6ITGB3

Chromosome 17source: Human Genome Project

Genes are arranged in linear order on chromosomes

Most frequent numerical anomalies in liveborn

AutosomesDown syndrome (trisomy 21: 47,XX,+21)

Edwards syndrome (trisomy 18: 47,XX,+18) Patau syndrome (trisomy 13: 47,XX+13)

Sex chromosomesTurner syndrome 45,X

Klinefelter syndrome 47,XXY

All chromosomesTriploidy (69 chromosomes)

Summary of Chromosome Anomalies

• Change in numbere.g. trisomy 21 Down syndrome;

Edwards’ syndrome; Turner syndrome.

Usually an isolated occurrence.

• Change in structuree.g. deletionsMay be inherited.

Trisomy 21

The DNA Double Helix

Disease-Associated Mutations Alter Protein Function

What is a mutation?

Mutation – an alteration or change in the genetic material

In clinical use usually = “harmful”InheritedFrom exposure to mutagenic agents but more

arise spontaneously through errors in DNA replication / repair

More likely to be recognized if effects are detrimental

Summary

Human body cells contain 46 chromosomes in 23 pairs – one of each pair is inherited from each parent

Chromosomes are made of DNAEach chromosome contains genes in a linear

order; like beads on a stringGenes are codes for cells to make proteinsAlterations in genes or chromosomes alter the

protein produced and can hence cause disease

http://syndrome.org/patau-syndrome/

http://www.healthofchildren.com/E-F/Edwards-Syndrome.html