I guess my question is going to sound pretty basic, but nevertheless I need to understand clearly how to use bwa .
I am not able to run a bwa indexing of the GRCh38 reference genome on my laptop, due to memory usage requirements (~5GB needed, according to the bwa man page).
The 1000 Genomes Project offers what seems to be an indexed version of it on its FTP servers.
Can I download the entire directory and use bwa locally for my alignments, without running a brand new indexing?
Try the igenomes of illumina
http://support.illumina.com/sequencing/sequencing_software/igenome.html
Huge zipped files but contain all the sequences you may need, indexed (for bwa, bowtie etc.) or not (chr fasta and full genomic fasta files)