Hello Steve, You are referring to the genomic? Hg19 is the official release from NCBI - we do not create it.
Concerning your questions, I suspect that both cases are somewhat true. Regions are replaced with refined basecalling and regions without sequence (perhaps with gaps or other placeholders) are filled in. I wouldn't expect the chromosomes to get longer - the sizes are pretty much a known (at least for human) and the gaps and other unsequenced or unsequence-able regions are held by strings of NNNN's as placeholders. For hg19, go to the gateway page and scroll to the bottom for credits and links to the source data. Check out the release notes to see any comments they have about the build process. Thanks, Jennifer ------------------------------------------------ Jennifer Jackson UCSC Genome Bioinformatics Group ----- "Steve Oh" <[email protected]> wrote: > From: "Steve Oh" <[email protected]> > To: [email protected] > Sent: Thursday, October 22, 2009 4:36:21 PM GMT -08:00 US/Canada Pacific > Subject: [Genome] question about build > > Hello, > > I am pulling some sequences from the current UCSC build from > Feb2009. I've noticed that some sequences are drastically different > > from even the previous build. Can you tell me how the new builds are > > constructed? Are new sequences that are added replacing previous > sequence (substituting), or are the new sequences inserted (making the > > overall genome size larger)? > > Thank you, > Steve Oh > > _______________________________________________ > Genome maillist - [email protected] > https://lists.soe.ucsc.edu/mailman/listinfo/genome _______________________________________________ Genome maillist - [email protected] https://lists.soe.ucsc.edu/mailman/listinfo/genome
