Read fast database with format fst. Use first column
of database (must be named `ind`) as rownames if desired. R/qtl2 routines assume data frames have
rownames to use to align individuals.
read_fast(datapath, columns = NULL, rownames = TRUE)extracted data frame with appropriate rows and columns.
character string path to database
names or indexes for columns to be extracted
use first column of rownames if TRUE (can supply column number)
read_fst