SREL
Reprint #2598
MITOCHONDRIAL
DNA VARIATION AMONG WINTERING MIDCONTINENT
GULF COAST SANDHILL CRANES
TRAVIS
C. GLENN, Department of Biological Sciences, University
of South Carolina, Columbia, SC 29208, and Savannah River
Ecology Laboratory, University of Georgia, Drawer E, Aiken,
SC 29802, USA
JONATHAN E. THOMPSON,2 Caesar Kleberg Wildlife Research
Institute, MSC 218, Texas A&M University-Kingsville,
700 University Boulevard, Kingsville, TX 78363, USA
BART M. BALLARD, Caesar Kleberg Wildlife Research Institute,
MSC 218, Texas A&M University-Kingsville, 700 University
Boulevard, Kingsville, TX 78363, USA
JAY A. ROBERSON, Texas Parks and Wildlife Department, 4200
Smith School Road, Austin, TX 78744, USA
JEFFREY 0. FRENCH, Department of Biological Sciences, University
of South Carolina, Columbia, SC 29208, and Savannah River
Ecology Laboratory, University of Georgia, Drawer E, Aiken,
SC 29802, USA
Abstract:
Based on morphological characteristics, 3 subspecies of
sandhill cranes (Grus canadensis) - the lesser sandhill
crane (G. c. canadensis). Canadian sandhill crane
(G. c. rowani) and greater sandhill crane (G.
c. tabida) occur within the midcontinent population
(MCP) and winter along the Gulf Coast of Texas, USA. Of
these subspecies, the greater sandhill crane is the least
abundant and the most restricted in distribution in the
midcontinent region, making it a subspecies of special concern.
Twenty individuals from each subspecies with the highest
posterior probabilities of membership in subspecies associated
with their morphological discriminant score (i.e. those
individuals that were least likely to be misclassified based
on the morphological model currently used to assign wintering
individuals to subspecies) were chosen from a total sample
of 220 birds. We amplified and sequenced a 437-base-pair
segment from domain I of the mitochondrial DNA (mtDNA) control
region for these 60 birds. Analyses of the resulting 41
different mtDNA haplotypes indicate that birds classified
as Canadian and greater sandhill cranes based on their morphology
do not differ genetically, but lesser sandhill cranes are
genetically distinct from both Canadian and greater sandhill
cranes. When Canadian and greater sandhill cranes are grouped
together, 55 of the 60 individuals sequenced are consistently
classified using morphology and mtDNA. We then used the
DNA sequences to develop a simple restriction enzyme assay
of this mtDNA segment to survey an additional 160 specimens.
These results indicate that (1) mtDNA assays provide reliable
discrimination of migratory sandhill cranes, (2) the current
subspecific designations of sandhill cranes may not accurately
reflect genetic structure in this species, (3) concern for
preserving the genetic diversity of sandhill cranes in the
midcontinent region may not need to focus on management
of greater sandhill cranes wintering in the sampled populations,
and (4) studies of individuals fromt he breeding grounds
are clearly needed to determine whether Canadian and greater
sandhill cranes are indeed distinct subspecies.
Key words:
crane, genetics, Grus canadensis, Gulf Coast, mitochondrial
DNA, sandhill crane, subspecies, Texas
SREL
Reprint #2598
