6.3.2: Applications of gene sequencing Flashcards
How many genes did scientists predict that the human genome would contain and how many did they find after the human genome was sequenced?
- 100 000 genes
- 24 000 genes
What does whole genome sequencing determine?
The complete DNA sequence of an organism’s genome.
-In the case of eukaryotic cells, that is the genetic material of the chromosomes, mitochondria and, if plants or algae, also, of chloroplasts.
Where are sequenced genomes stored?
Gene banks.
We share over 99% of our genes with chimpanzees. what does this verify?
-That genes that work well tend to be conserved by evolution.
Give an example of how useful genes are conserved by evolution.
-Pigs and humans have similar genes for insulin.
Sometimes, as evolution progresses, some genes are co-opted to perform new tasks. Give an example of this.
Tiny changes to a gene in humans called FOXP2, which is found in other mammals including mice and chimpanzees, means that in humans this gene allows speech.
Many of the differences between organisms are not because the organisms have totally different genes but because…
…some of their shared genes have been altered and now work in subtly different ways.
-Some changes to the regulatory regions of DNA that do not directly code for proteins also have also altered the expression of the genomes.
How do regulatory and coding genes interact?
-They interact in such ways that, without increasing the number of genes, the numbers of proteins made can be increased.
What has comparing the genomes of organisms thought to be closely related species allowed us to do?
- Helped us to confirm their evolutionary relationships.
- Has led to new knowledge about their relationships.
- In some cases , certain organisms have been reclassified.
How do we verify an animal’s evolutionary history?
-The DNA from bones and teeth of some extinct animals can be amplified and sequenced.
In humans, what percentage of our DNA is not shared with others?
0.1%
What are the places in our DNA where mutations such as substitutions occur called?
- single nucleotide polymorphisms, or SNPs (pronounced ‘snips’.
- Some have no effect on the protein, some can alter a protein or alter the way a piece of RNA regulates the expression of another gene.
What plays a major role in regulating gene expression in eukaryotic cells?
Methylation of certain chemical groups in DNA.
What can methods to map the methylation of the whole human genomes help researchers to understand?
The development of certain diseases, for example certain types of cancer and why they may or may not develop in genetically similar individuals.
-The study of this aspect of genetics is called epigenetics.
How has genome sequencing helped us to determine the amino acid sequence of proteins?
- Determining the sequence of amino acids within a protein is laborious and time consuming.
- If you have the organism’s genome and know which genes code for a specific protein, by using knowledge of which base triplets code for which amino acids, they can determine the primary sequence of proteins.
