WEEK 2 (Draft sequences & Checking for errors) Flashcards
Why are genomes sequenced more than once?
To enhance the level of accuracy
What is Compiling?
The assembly of a final or reference sequence from multiple sequencing runs
What does Coverage/Depth of sequencing refer to?
The number of times a specific nucleotide appears in the same position within a sequence after multiple reads have been compiled
Why are generation sequencing approaches considered “deep sequencing” methods?
Because they allow for multiple reads of a sequence
What does annotation rely on?
- Bioinformatics
- Different software tools
Describe the process “Annotation”
Genome projects accumulate nucleotide sequences, and then scientists have to make sense of those sequences. After a genome is sequenced and compiled, scientists have to IDENTIFY GENE-REGULATORY SEQUENCES and other sequences in the genome so GENE MAPS can be developed
Describe an approach to annotating a sequence
Compare the newly sequenced genomic DNA to the known sequences already stored in various databases
What does the NCBI provide access to?
BLAST
[BASIC LOCAL ALIGNMENT SEARCH TOOL]
What is Blast?
A very popular software application for searching through banks of DNA and protein sequence data
Describe one approach to assigning functions to genes
Use sequence similarity searches such as BLAST to search through databases to and alignments between the newly sequenced genome and genes that have already been identified
What is one benefit of similarity searches?
They are often able to identify homologous genes (genes that are evolutionarily related)
What are paralogs?
Homologous genes in the same species
Give an example of a paralog
Alpha and beta globin subunits in humans are paralogs resulting from a gene-duplication event
Paralogs often have similar or identical _________________
Functions
When are genes known as Orthologs?
If homologous genes in different species are thought to have descended from a gene in a common ancestor
