Human Cells Human genomics Higher Human Biology Human Cells Human genomics

What do you know? Human genomics is the study of the human genome working out the nucleotide sequences on DNA. Relating the sequence to genes Relating genes to their function WHAT DO YOU KNOW ON THIS SUBJECT?

a. Sequencing DNA YOU SHOULD KNOW What bioinformatics is. How modern DNA is analysed. What systematic genome studies are What the implications are of genome studies and personalised health treatments

Human genome project Project to map all nucleotides in a typical human’s DNA Started in 1990 finished in 2003 Shared between laboratories including UK and US Using DNA sequencing tools including modified nucleotides, fluorescent dyes, electrophoresis and computers The typical human genome consists of 3 billion nucleotides base pairs

Comparing individual genomes Variations in DNA can be anaylsed down to single changes in base pair nucleotides These are called single nucleotide polymorphisms (SNP) 1 million already identified with exact location and used as DNA markers Used as a tool in biomedical research

Bioinformatics Bioinformatics has increased the speed at which the genome can be analysed The information is now analysed by computers and shared on the internet 3 areas to bioinformatics Molecular biology (e.g. sequencing) Statistical analysis Computer technology

Bioinformatics Computerisation allows data to be analysed very quickly including: Protein-coding sequences similar to known genes Start sequences of nucleotides where a coding sequence usually follows Sequences lacking stop codons (as these usually have coding sequences before them) Bioinformatics allows investigation into inheritance, evolutionary biology and personalised medicine

Systematics Studying living things in relation to their diversity, relatedness and classification Human genome sequences being compared to other genome sequences to look at evolutionary relationships and origins Humans thought to originate in Africa Developed to give distinct genetically different populations (millions of years) Group moved out of Africa (approx. 100,000 years ago) to spread around the world

Mitochondrial DNA analysis Mitochondrial DNA is inherited from female parent and not mixed with other DNA Y chromosome in males also does not mix with other DNA during meiosis Mitochondrial DNA can be used to accurately trace changes to DNA in populations

Personalise medicine Your personalised genome sequence can be mapped. It is becoming cheaper and faster to map using computerised machinery Personalised medicine may be possible as human understanding of the genetic component of disorder/disease is better understood How will that be a good or bad thing?

Mutations in humans As the sequence is analysed changes will need to be identified for: Neutral mutations (having no negative effect) Harmful mutations (having a negative effect) These could include non functioning protein code, non-coding for protein which give rise to genetic disorders or disease Identified 2200 genetic disorders and diseases in humans Need to analyse the cause for these (very complex) Need to consider genetic and environmental influences

Pharmocogenetics Studying the effects of pharmaceutical drugs on the human population It is hoped in future drug efficacy will be able to be matched to genome of individuals for types and doses

The Future DNA variations linked to diabetes, heart disease, cancer, obesity, etc? What are the ethical issues related to knowing this information Offspring Employers Insurance Laws

What have you learned? What is bioinformatics? What are the 3 areas that contribute to bioinformatics? What are the computer programmes look for when analysing the coding sequences? What is systematics in relation to genetics? Why is it useful to know other species genomes? What types of mutations is it important to distinguish between? What is pharmacogenetics? How could personalised medicine be realised?

Reinforcement Read chapter pages 63 to 70 Complete questions on page 70 Read Scholar section Make own notes

Amplifying and detecting DNA sequences What you should know The process called Polymerase Chain reaction (PCR). What DNA probes are and what they are used for. The application of DNA profiling.

Polymerase Chain Reaction (PCR) The technique used to produce multiple copies (amplify) of a piece of DNA It is a computerised mechanised process that takes place outside the body (in vitro) The process needs The original DNA Primers (small sections of DNA complimentary to the 3’ end of the DNA to be copied) Nucleotides DNA polymerase (heat stable)

PCR The original strand is heated to approx. 95oC to break H bonds Cool to approx. 55oC to allow the primers to bind to its target sequence at 3’ ends Heat to 72oC and nucleotides will join from primer ends by DNA polymerase This produces 2 complete strands of DNA Repeat the whole process many times to give amplification of DNA (multiple copies) Think if the process was repeated 10 times how many DNA strands would be present at the end? 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024

DNA probes DNA probes are short sections of single stranded DNA They are capable of binding to a specific sequence of nucleotides They can be labelled with fluorescent markers to all them to be detected Collections of different DNA probes labelled with markers are used to identify a specific sequence on DNA

Uses of amplifying DNA - medical Small quantities of DNA can be amplified Specific sequences of DNA can be studied that are linked to genetic disorders/diseases This can help with diagnosis if family history suggests disorder is present This can help with estimating onset of genetic disorder/disease by identifying possible mutations in the genome

Uses of amplifying DNA - forensic Human genome contains non-coding regions of DNA (introns) These often have repeated sequences of code They are randomly distributed in the genome They are unique to individuals and can be used to identify a person’s DNA They give the characteristic DNA profile banding patterns This can in paternity disputes, missing person id, disaster missing persons id

What have you learned? What is PCR? What are the 4 steps to the PCR process? What are DNA probes? What is needed to detect the DNA probes? What are the applications of DNA profiling? What are used to identify individuals when profiling DNA?

Reinforcement Read textbook pages 71 to 76 Answer questions on page 76 Complete summary on pages 76 and 77 Complete multiple choice questions chapter 5 Read Scholar Go over PPT on blog Make own notes from reading Complete homework booklet on chapters 4 and 5 by Friday