Short Answer: NCBI and Ensembl limit the server access for individual connections. Hence, when hundreds of retrieval queries are sent to download hundreds of genomes, it may happen that some of the queries get cancelled after a certain count. In that case, simply re-run the corresponding
meta.retrievalfunction and it will pick up where it left off.
biomartr package different from the BiomaRt package that I have been using so far?
Short Answer:
biomartris designed for the retrieval of big datasets such as multiple genomes, proteomes, annotation, etc whereasbiomaRtis designed for the retrieval of small data such as sequences of individual genes