9327

• UCREFRP Catalog Number: 9327
• Author: Starnes, W. C.
• USFW Year: 1995.
• Copyright Material: NO

LDH-A displayed one variant individual heter.ozygotic for slow-
fast alleles in the Rio Sinaloa, Mexico, sample whereas all other
members of that and all other population samples were homozygous
for the faster. MDH-2 had one occurrence of a slow allele each
at Westwater and Black Rocks canyons and two in the Little Snake
River sample, all upper Colorado Basin localities. MDH-3 had one
homozygote for a slower allele in the Debegple Canyon sample and
one for a faster in Desolation Canyon. TPI-2 displayed one
homozygote for a faster allele in the Cienega Creek (Gila Basin).
The invariability of these loci renders them noninformative and
they will not be further discussed with regard to results of this
report.
Mexican Pacific Drainages
Several loci yielded relatively unambiguous implications
with regard to the genetic distinctness of Mexican Gila
populations. First off, there are several patterns of variation
that serve to delimit several samples which, when taken as a
group, have genetic integrity. These are from a set of rivers
which includes the rios Culiacan, Sinaloa, Fuerte, Mayo, and
portions of the complex Yaqui drainage (Fig. 1).. Alleles were
highly similar in these drainages (Figs. 2-12), sufficiently so
that samples from the first three drainages mentioned were
combined to accommodate limitations of BTOSYS.. Tough some
frequency differences exist between samples at two loci (see
discussion below). The integrity of the group in question is
exemplified by the UPGMA cluster analyses based on similarity
performed by BIOSYS; the grouping stands in all configurations of
the data set subjected to analysis (Figs. ]3-16). The results
thereof closely group samples from those three drainages with
samples from the Mayo, lower Yaqui, and Tomochi.c portion of the
eastern upper Yaqui in the Rio Aros arm (Fig. 1). These are in
turn most similar to but well separated from a pair consisting of
samples from the San Bernadino preserve, AZ (n-4), in the extreme
northern upper Yaqui proper arm and from the Rio Matape drainage
to the northwest of the Yaqui. This grouping is well separated
from all other Gila examined. Two samples from the Rio
Papigochic system in extreme easterly portions of the Rio Aros
arm of the Yaqui drainage group with samples taken from
populations to the north in the Rio Grande-Pecos, Guzman, and
Colorado Basins.
Allelic Variation
Allelic variation at informative loci outlined below serves
to delimit the aforesaid taxonomic unit. There are fixed and
nearly fixed differences at several loci that indicate that the
samples from the Culiacan, Sinaloa, Fuerte, Mayo, lower Yaqui
drainages, and Tomochic portion of the eastern Yaqui headwaters
2