1.5 Human Genomics Flashcards
What is the genome of an organism?
The complete set of genetic material (DNA) it possesses
What has advances in faster and cheaper computer processing made possible?
To determine the sequence of DNA bases for entire genomes
What is human genomics ?
The study of the human genome
What was the human genome project an effort of ?
The international scientific community to sequence the entire human genome using the most advanced technology
What are the years of the human genome project ?
1990-2001
Why did the project finish 4 years ahead of schedule?
Due to advanced in technology and understanding
How many base pairs are there in every human cells?
Around 3 billion
How many genes are there around in each individual?
20-30000
How many genes are disease coding genes ?
300
How many genes are protein coding genes ?
4000
How many proteins do these genes code for?
2 million
What percentage of our genome codes for protein ?
1-2%
What percentage of our genome help control translation?
24%
What is bioinformatics ?
Name given to the field where biological, statistical and computer modelling are used to analyse the sequence of bases in DNA and the sequence of amino acids in proteins
By sequencing genomes what is possible ?
To pin point known sequences within it
What is systematics ?
The field which compares genomes (particularly the human genome) to the genomes of other species
What can systematics be defined as?
The study of a group of living things with respect to their diversity, relatedness and classification
What does systematics allow scientists to develop?
An evolutionary pathway and discover species which may have shared a common ancestor
To sequence DNA what is required ?
Large volumes of DNA fragments are required
What can many copies of a specific segment of DNA can be produced using technique called?
Polymerase chain reaction
What does PCR allow us to do?
Amplify a DNA fragment to produce vast quantities to work with quickly and efficiently
In Oder to amplify DNA what must be present ?
Many of four free nucleotides of DNA
Primers
Heat-tolerant DNA polymerase (Taq polymerase)
Template DNA to be replicated
What is stage 1 of PCR ?
The DNA is mixed with DNA polymerase and primers. DNA is heated to 95’c in order to separate the two strands by breaking the hydrogen bonds between the complementary bases. This is called denaturing.
What is stage 2 of PCR ?
The DNA is cooled to 55’c. Cooling allows the complementary primer to bind/anneal to the specific target sequence on the DNA to be copied. This is called annealing.
What is stage 3 of PCR ?
DNA heated to 72’c and then heat-tolerant DNA polymerase replicates the fragments of DNA by joining free DNA nucleotides together using the primer as a starting point
What is a DNA probe?
A short, single-stranded, manmade fragment of DNA that is complementary to the specific sequence of DNA bases that are being tested
What will happen to the probe of the target sequence is present?
The probe will bind to it via complementary base pairing
How can the probe be detected ?
Using radioactive or more often now FLUORESCENT LABEL
What can DNA probes be used to detect?
Single gene mutations
What is a DNA probe used to detect?
The presence of specific DNA base sequences in a sample of DNA
What is stage 1 when using a DNA probe to identify base sequences ?
DNA is denatured and cut into fragments of varying lengths
What is stage 2 when using a DNA probe to identify base sequences ?
The fragments are separated according to length by gel electrophoresis
What is stage 3 when using a DNA probe to identify base sequences ?
A fluorescent / radioactive probe with a known base sequence is added. If it is complementary to a base sequence on a fragment it will bind via complementary base pairing
What is stage 4 when using a DNA probe to identify base sequences ?
The florescence of the probe indicates if there is a match using X-ray film
What are DNA probes also used in ?
paternity cases
for solving crmes
How can DNA probes be used to solve crimes?
by comparing regions of the genome with highly variable repetitive DNA sequences and matching them to a sample
What does sequencing the genome and identifying possible mutations do?
predict the risk of a genetic condition and hence employ techniques to reduce the risk.
the ability to screen a cell sample for a specific base sequence allows medical professionals to provide personalised medicine.
By understanding the link between a persons genes and the relationship these genes share with certain diseases what is possible?
to provide treatment which is specific to the individual
What is the name given to the approach where a patients treatment is specifically geared to them, potentially resulting in increased efficiency of treatment whilst reducing side effects?
pharmacogenetics
What is the only way generalised medicine can be abolished?
by a deep appreciation of the relationship between specific genes, the nature of their transcription and the proteins they code for.
Each human has an almost identical genome. However, what is within the genome which makes each human genome unique?
regions of highly variable numbers of repetitive sequences (VNTRs) of DNA
What does the frequency, number and distribution of these repetitive sequences of DNA construct ?
an individuals DNA profile
What is a useful tool in DNA profiling especially for crime scenes.
PCR
