... Evolution of the coalescence rate of double neutron stars (NS) and neutron star - black hole (BH) binaries are computed for model galaxies with different star formation rates. Assuming gamma-ray bursts (GRB) to originate from NS+NS or NS+BH merging in distant galaxies, theoretical - distributions for gamma-ray bursts (GRB) are calculated for the first time taking the computed merging rates into account. ... Effect of sources evolution on - distribution and -test. ...