There is only one file type that uses the .LAV extension:
DNA Sequence Alignment File
A LAV file is a data file created by LASTZ, or its predecessor BLASTZ. It contains alignment blocks of DNA sequences organized in matrices. LAV files are used to identify similar structural, evolutionary, and functional relationships between DNA sequences.
LASTZ, and its predecessor BLASTZ, are nucleotide local alignment programs that support human chromosomes. The programs can import FASTA and NIB DNA sequences and output them in the LAV format. The LAV format was developed by Webb Miller and his group at the Miller Lab at Penn State University (PSU).
Updated: March 21, 2017