In order to be able to examine the alignments more effectively we will convert the format from FASTA to NEXUS format. This will make it easier to see the alignment.seqmagick convert --output-format nexus --alphabet dna bovidae_50_mtDNA-named.fa bovidae_50_mtDNA-named.nexLook at the NEXUS alignment file. At the beginning of the alignment and near the end there are regions that have large gaps and very poor conservation.Q2. What is the reason for this? (Hint: use the accession numbers in the name to search Entrez for the annotation.)
Question
In order to be able to examine the alignments more effectively we will convert the format from FASTA to NEXUS format. This will make it easier to see the alignment.seqmagick convert --output-format nexus --alphabet dna bovidae_50_mtDNA-named.fa bovidae_50_mtDNA-named.nexLook at the NEXUS alignment file. At the beginning of the alignment and near the end there are regions that have large gaps and very poor conservation.Q2. What is the reason for this? (Hint: use the accession numbers in the name to search Entrez for the annotation.)
Solution
The reason for large gaps and poor conservation at the beginning and end of the alignment could be due to several factors:
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Sequencing Errors: These are common in next-generation sequencing technologies. They can occur due to various reasons such as PCR errors, sequencing machine errors, or sample preparation errors.
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Evolutionary Divergence: The regions with poor conservation could be highly variable regions that have evolved differently in different species. These regions might not have a crucial function, allowing for more mutations to occur without detrimental effects.
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Annotation Errors: The accession numbers in the name can be used to search Entrez for the annotation. If the annotation is incorrect or incomplete, it could lead to gaps in the alignment.
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Structural Variations: Large gaps could also be due to structural variations in the DNA, such as insertions, deletions, or inversions. These variations can cause misalignment between sequences.
To confirm the exact reason, you would need to look at the specific sequences and possibly perform further analysis or experiments.
Similar Questions
The phylogenetic reconstruction methods we will be using cannot handle missing bases, so these must be removed. We can use Gblocks to remove the non-conserved regions of the alignment. Run Gblocks by entering Gblocks.You should see something like this:****************************************************** GBLOCKS 0.91b SELECTION OF CONSERVED BLOCKS FROM MULTIPLE ALIGNMENTS FOR THEIR USE IN PHYLOGENETIC ANALYSIS ******************************************************o. Open Fileb. Block Parameterss. Saving Optionsg. (Get Blocks)q. QuitUse the menu options in the program to remove the non-conserved regions from the fa file (not the nex file). This will give you a file bovidae_50_mtDNA-named.fa-gb.Q3. Why do we need to do this? (Hint:read the Gblocks documentation)
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