Genome projects

Question 1

What is bioinformatics

Answer 1

• The science of collecting and analysing complex biological data such as genetic codes.
• It uses computers to read, store and organise biological data at a much faster rate than previously.
• It utilises algorithms to analyse and interpret biological data.

Question 2

How is a map of a genome obtained

Answer 2

By mapping the DNA base sequences that make up the genes of the organism and then to map these genes onto the individual chromosomes of that organism

Question 3

How do we determine the whole DNA base sequence of an organism

Answer 3

• Determining the complete DNA base sequence of an organism uses the technique of whole-genome shotgun (WGS) sequencing.
• This involves researchers cutting the DNA into many small, easily sequenced sections and then using computer algorithms to align overlapping segments to assemble the entire genome.
• Sequencing methods such as these are continuously updated which, along with the increased automation of the process involved, have led to extremely rapid sequencing of whole genomes.

Question 4

What are single nucleotide polymorphisms (SNPs)

Answer 4

Single-base variations in the genome that are associated with disease and other disorders

Question 5

How many SNPs have been found in the human genome

Answer 5

Over 1.4 million

Question 6

What is the proteome

Answer 6

All of the proteins produced by the genome

Question 7

What is the cellular proteome

Answer 7

All of the proteins produced by the genome in a given type of cell

Question 8

What is the complete proteome

Answer 8

All of the proteins produced by the genome in a particular organism

Question 9

What was the first bacterium to have its genome fully sequenced and how many genes does it contain

Answer 9

• Haemophilus Influenza in 1995
• H. Influenza contains 1700 genes comprising of 1.8 million bases

Question 10

What projects are there currently that aim to map the genome of simple prokaryotic organisms and why is it thought to be helpful

Answer 10

• The genomes of thousands of single-celled prokaryotic organisms are currently being sequenced as part of the Human Microbiome Project.
• It is hoped that the information gained will help cure disease and provide knowledge of genes that can be usefully exploited.
• For example, ones from organisms that can withstand extreme or toxic environmental conditions and so have potential uses in cleaning up pollutants or in manufacturing biofuels.

Question 11

Is determining the proteome of prokaryotic organisms such as bacteria easy or difficult

Answer 11

Easy

Question 12

Why is determining the proteome of prokaryotic organisms relatively easy

Answer 12

• The vast majority of prokaryotes have just one, circular piece of DNA that is not associated with histones.
• There are none of the non-coding portions of DNA which are typical of eukaryotic cells.

Question 13

What are the potential applications of knowing the proteome of organisms such as bacteria

Answer 13

• We can identify the proteins that acts as antigens on the surfaces of human pathogens.
• These antigens can be used in vaccines against diseases caused by these pathogens.

Question 14

What is and example of how determining the proteome of a bacterium is being used in vaccine technology

Answer 14

• Sequencing the DNA of Plasmodium Falciparum which causes malaria.
• All 5300 genes on Plasmodium’s 14 chromosomes have been sequenced giving us an insight into its metabolism and knowledge of the proteins it produces.
• This will be invaluable in producing a malaria vaccine.

Question 15

Describe how far we have got in determining the genome and proteome of complex organisms such as humans and what the potential problems are

Answer 15

• We successfully mapped the human genome in 2003.
• There are around 20,000 genes in the human genome although this number is constantly being revised as we improve our understanding of the genome.
• The problem in complex organisms is translating the knowledge of the genome into the proteome.
• This is because the genome of complex organisms contains many non-coding genes as well as genes which have a role in regulating other genes.
• In humans, it is thought that around 1.5% of the genes may code for proteins.
• There is a human proteome project currently underway to identify all of the proteins produced by humans
• There is also a question of whose DNA is used for mapping as everyone’s DNA sequence is slightly different.