Before revision:  But the statistical limitations of these models, which can have millions of parameters and are fit to MSAs of only hundreds or thousands of effective sequences using a procedure known as inverse Ising inference, are incompletely understood.
After revision:  But the statistical limitations of these models, which can have millions of parameters and are fit to MSAs of only thousands or hundreds of effective sequences using a procedure known as inverse Ising inference, are incompletely understood.