New
report available:
Chivers,
S.J., R.W. Baird, K.M. Martien, B.L. Taylor, E. Archer, A.M. Gorgone, B.L.
Hancock, N.M. Hedrick, D. Matilla, D.J. McSweeney, E.M. Oleson, C.L. Palmer, V.
Pease, K.M. Robertson, J. Robbins, J.C. Salinas, G.S. Schorr, M. Schultz, J.L.
Theileking, and D.L. Webster. 2010. Evidence
of genetic differentiation for Hawai”®i insular false killer whales (Pseudorca
crassidens). NOAA
Technical Memorandum NMFS-SWFSC-458, 46p
Chivers et al. (2007) found Hawai”®i
insular false killer whales to be distinct from other strata within the
Indo-Pacific Ocean using mitochondrial DNA (mtDNA) control region sequence
data. Here, we add new samples and eight nuclear DNA (nDNA) microsatellite markers
to that study. After extensive quality checking, some haplotypes and duplicate individuals
were removed from the 2007 mtDNA data set. A strong phylogeographic signal consistent
with local haplotype evolution was evident for Hawai”®i insular false killer
whales with all but one individual having one of 2 closely related haplotypes
found only in this population. The mtDNA characteristics of the Hawai”®i insular
false killer whales (n
=
81) differed significantly (all p-values for
Fisher exact and ¦µST
<0.0001)
from both broad-scale strata (Central North Pacific (n = 13) and
Eastern North Pacific (n = 39)), and all fine-scale strata (Hawai”®i
pelagic (n
=
9), Mexico (n
=
19), Panama (n
=
15) and American Samoa (n = 6)). The magnitude of mtDNA
differentiation (all ¦µST
>0.68)
was consistent with less than one migrant per generation. The nDNA marker
results were highly significant with all Fisher exact p-values ӆ 0.001
for comparisons of the Hawai”®i insular stratum (n = 69) to the
broad-scale strata (Central North Pacific (n = 13) and
Eastern North Pacific (n = 36)), and fine-scale strata (Hawai”®i
pelagic (n
=
9), Mexico (n
=
19), Panama (n
=
12) and American Samoa (n = 6)). The magnitude of differentiation
was much less for nDNA (0.01 < FST < 0.08, 0.01 < JostӮs D <
0.06) than for mtDNA, indicating the potential for some male-mediated gene flow
although the possibility that FST is low because of the high mutation
rate of microsatellites or the influence of selection operating to counter gene
flow cannot be excluded. Inferences from these data are limited by sample
distribution, with pelagic false killer whales near the Hawaiian Islands
inadequately sampled. However, the small number of Hawai”®i insular false killer
whales (around 120) together with an estimated effective population size of
44.3 (95% CI = 31.2-67.2) are causes for concern about loss of genetic
diversity.
A
pdf copy can be downloaded from http://swfsc.noaa.gov/publications/TM/SWFSC/NOAA-TM-NMFS-SWFSC-458.pdf
or www.cascadiaresearch.org/hawaii/falsekillerwhale.htm
=============================================================================
Robin W. Baird, Ph.D.
Research Biologist
Cascadia Research Collective
218 1/2 W. 4th Avenue
Olympia, WA
98501 USA
www.cascadiaresearch.org