Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
In the version of this article initially published, the sequence of primer VH3a-sense in Table 1 incorrectly indicated a ‘C’ at position 12 instead of a ‘G’. The error has been corrected in the HTML and PDF versions of the article.
