The human genome project and 100k genome project

What were the aims of the human genome project?

• Improve knowledge and understanding of genetic disorders to improve diagnosis and treatment

• Identify all genes and what chromosome they are on

• Determine the sequence of all 3million base pairs of DNA

• Improve tools for data analysis

• Transfer technology to the private sector to develop medical innovation

• Address ethical, legal and social issues that may arise

What did the Human Genome Project find?

• Humans have roughly 20500 genes

• There were more repeated sections of DNA than expected

• Fewer than 7% of families of proteins are specific to vertebrates, showing the close relationship between all living organisms

When did the human genome project start, how long did it take and how much did it cost?

Started in 1990, took 13 years and cost 2.7 billion dollars

How did the HGP use Sanger sequencing?

Used Sanger Sequencing to sequence small sections of DNA.

How did the 100k Genome Project develop technology?

Used New Generation Sequencers that could sequence an entire genome in a few hours

What was the 100k genome project?

A project which launched in 2012 to sequence 100k genomes of individuals with rare diseases/cancer

What were the aims of the 100k genome project?

• Create an ethical and transparent programme based on consent

• Set up a genomic service for the NHS to benefit patients

• Enable medical and scientific discovery

• Develop a UK genomics industry

What are the applications of the 100k genome project and HGP?

Scientists now know which sections of DNA code for many inherited diseases and their location on a chromosome, which means an individual can be tested to see if they carry a gene to at leads to disease development.

Describe the process of Sanger Sequencing

• DNA is broken into single stranded fragments about 1000 bases long.

• Complementary strands are synthesised using dideoxynucleotides, primers and DNA polymerase.

• The complementary strand is synthesised and when a dideoxynucleotide binds synthesis stops.

• Gel electrophoresis sorts the DNA strands by size

Describe the methods of gene testing

• Bases in the patients gene can be compared to the normal version of the gene

• A DNA probe can be used. This is a single strand of DNA complementary to the mutated sequence. The probe attaches to the mutated area and flags it up.

What can be tested using gene testing?

• Carrier screening

• Pre Natal testing

• Newborn screening tests

• Presymptonic testing

• Confirmation/diagnosis

• Forensics/identity testing

What are the ethical issues with gene testing?

• Identification of allele sequences has let scientists scan a patients DNA sample

• Embryo screening to detect disorders

• Concerns related to the possibility of screening for adult onset disorders such as dementia

• Screening embryos had lead to concerns over choosing alleles

• Concerns of discrimination and social stigmatisation outweighing the benefits of gene testing

• Use of genetic screening and genetic counselling

• Concerns regarding ownership of genetic information

Pros of gene testing

• Improved lives

• Tests can clarify diagnosis and direct towards beneficial treatment

• Allows couples to avoid having children with high risk disease

• Identify people at risk for conditions

Cons of gene testing

• Difficulty interpreting results as some who carry a disease related mutation don’t develop it

• Possibility for lab errors, misidentification and contamination

• Anxiety provoking

• Parents may terminate child

• Issues with who owns data

Why were the Anopholes gambiae and P. Falciparums genome sequenced?

Allows better methods to control malaria.

The P. Falciparum had developed multi drug resistance.

Sequencing of Anopholes gambiae allows scientists to develop chemicals which could stop insecticide resistance.

Sequencing of P falciparum is allowing for development of more effective drugs

What is the method of killing the vector in relation to malaria?

In 2015, CRISPR Cas9 was used as a gene editing technology to modify mosquito eggs, adding a gene making them synthesise an antibody against plasmodium, killing plasmodium.

What is the method of killing the parasite in relation to malaria?

Generally use quinine medication to disrupt the plasmodium digesting haemoglobin but mutations have led to resistance. The genome was sequenced in 2002 to develop more effective drugs