0e9g Bell Ringer #1 Think 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 genes Be 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 chromosomes XY = sex chromosome constitution (XY = male, XX = female). Any further description would refer to any abnormalities or variants found

Total Genes On Chromosome: genes in region marked red, 20 are shown FZD2 AKAP10 ITGB4 KRTHA8 WD1 SOST MPP3 MLLT6 STAT3 BRCA1breast cancer 1, early onset GFAP NRXN4 NSF NGFR CACNB1 HOXB9 HTLVR ABCA5 CDC6 ITGB3 Chromosome 17 source: Human Genome Project Genes are arranged in linear order on chromosomes

Most frequent numerical anomalies in liveborn Autosomes Down syndrome (trisomy 21: 47,XX,+21) Edwards syndrome (trisomy 18: 47,XX,+18) Patau syndrome (trisomy 13: 47,XX+13) Sex chromosomes Turner syndrome 45,X Klinefelter syndrome 47,XXY All chromosomes Triploidy (69 chromosomes)

Summary of Chromosome Anomalies Change in number e.g. trisomy 21 Down syndrome; Edwards’ syndrome; Turner syndrome. Usually an isolated occurrence. Change in structure e.g. deletions May 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” Inherited From 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 DNA Each chromosome contains genes in a linear order; like beads on a string Genes are codes for cells to make proteins Alterations in genes or chromosomes alter the protein produced and can hence cause disease

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