GENETIC-ANALYSIS OF HYBRID ZONES - NUMBERS OF MARKERS AND POWER OF RESOLUTION

The use of molecular genetic techniques is becoming increasingly wides pread in analyses of hybrid zones. Yet, exactly how many molecular mar kers are required to provide a given degree of resolution remains an o pen question. We present statistical models that relate the number of markers examined to their power to discriminate between pure species, F1's, and backcross individuals. Our models indicate that only about f our or five markers are required to provide a coarse classification of individuals in hybrid zones, whereas upwards of 70 markers are requir ed to discriminate between pure species and advanced backcrosses. The models provide hybrid zone researchers a basis upon which to balance t he time and expense of examining large numbers of markers against the magnitude of classification errors when smaller numbers of markers are examined.