Merkouris et at: Genetic diversity in Chionoecetes bairdi and C opilio 
531 
Table 3 (continued) 
PROT-3* SOD-1 * TPI-1* 
Population 1 2 
n 
noo 
*88 
n 
*100 
*109 
n 
*-100 
*100 
*-41 
Chionoecetes bairdi, continued 
Kachemak Bay 1990 
50 
— 
1.000 
50 
1.000 
— 
50 
1.000 
— 
— 
Prince Wm. Sd. 1990 
50 
— 
1.000 
50 
1.000 
— 
50 
1.000 
— 
— 
Sullivan Is. 1993 
100 
— 
1.000 
ND 
100 
1.000 
— 
— 
Seymour C. pooled 
125 
— 
1.000 
125 
1.000 
— 
125 
1.000 
— 
— 
Chionoecetes opilio 
Bering Sea pooled 
124 
0.992 
0.008 
122 
1.000 
- 
125 
0.992 
0.004 
0.004 
St. Matt. Is. pooled 
196 
0.997 
0.003 
198 
0.997 
0.003 
198 
0.995 
0.002 
0.002 
Pribilof Is. pooled 
214 
0.986 
0.014 
211 
0.998 
0.002 
214 
1.000 
— 
— 
Atlantic 0. 1991 
97 
1.000 
— 
97 
1.000 
— 
97 
0.990 
0.010 
— 
1 Port Moller, Sand Point/Pavlof Bay, and Prince William Sound C. bairdi populations not included in analyses. 
2 G3PDH-1*87 was pooled with *100. 
were grouped by major geographic regions (Bering 
Sea, Gulf of Alaska, and Southeast Alaska) for com- 
parison, the overall log-likelihood statistic was highly 
significant (P<0.01, Table 4). G3PDH-2* and PROT- 
3* contributed most to the observed among-region 
heterogeneity. Within the Bering Sea, pooled samples 
collected from Bristol Bay (east of approximately 
162°45’W long.) were significantly different from 
pooled samples from the Bering Sea and Pribilof Is- 
land areas (west of approximately 167°00'W long.). 
In this comparison, G3PDH-2* , IDHP-1*, and PEPA * 
allelic frequencies differed significantly. 
The following were the low-frequency alleles detected 
according to their respective major geographic regions: 
1) Bering Sea, AAT-2*69, ALAT*87, CBYR*117 , 
G3PDH-2*86 , GPI-A1*55, MDH-A1*79, PGDH*112, 
PGM- 1*103, and PROT-3* 100\ 2) Gulf of Alaska, AAT- 
1*64, PGDH*91, and PGM-1*75\ and 3) Southeast 
Alaska, MDH-A1 *128 and PGM- 1 *88. The PROT-3* 100 
allele, likely an introgressed C. opilio allele, contrib- 
uted significantly to the overall heterogeneity observed 
among the major geographic regions of Bering Sea, Gulf 
of Alaska, and Southeast Alaska. Genetic distance 
measurements (Cavalli-Sforza and Edwards, 1967) 
within C. bairdi populations ranged from 0.031 to 0.059. 
Chionoecetes opilio 
Twenty-nine loci were scored consistently in all col- 
lections and were used in the data analyses. No sig- 
nificant temporal variation (P<0.01) was found 
within multiple-year collections in the Bering Sea, 
St. Matthew Island, and the Pribilof Islands. We 
pooled these collections for further analyses. 
Seventeen loci, AAT-1*, AAT-2* , AH-2* , AH-3*, 
CBYR*, G3PDH-1*, G3PDH-2*, GPI-A1*, IDHP-1*, 
MDH-A1*, MDH-A2*, PEPA*, PGDH*, PGM-1*, 
PROT-3*, SOD- 1 *, and TPI- 1 *, were polymorphic in at 
least one population (Table 3). Twelve monomorphic 
loci were ADA-1*, ADA-2*, ADA-3*, ALAT*, pGALA*, 
GAPDH*, PGLUA*, MEP-1*, MP1 *, PEPD-2*, PROT- 
1 *, and PROT-2*. One polymorphic locus, AH -3*, was vari- 
able at a frequency of >0.05 in at least one population. 
Genotype frequencies at all loci conformed to 
Hardy- Weinberg expectations; therefore we assumed 
all samples were from single panmictic populations. 
Average observed heterozygosities were lower than 
those for C. bairdi and ranged from 0.012 to 0.013 in 
Alaskan populations; the average heterozygosity was 
0.010 in Atlantic Ocean C. opilio. 
Among-population variation 
F st of 17 polymorphic loci was not significantly dif- 
ferent from zero for Alaskan populations (P=0.4270) 
or when the Atlantic Ocean collection was included 
(P=0.7130). However, the F gT value for PGM-1* was 
highly significant (P=0.0050) in comparisons of At- 
lantic Ocean and Alaskan C. opilio. A hierarchical 
log-likelihood analysis of these loci revealed very low 
levels of heterogeneity among all C. opilio (Table 5). 
In this analysis, PGM-1* was also highly significant 
(P=0.0071) in comparisons of Atlantic Ocean and 
Alaskan C. opilio. Among all C. opilio, PGM-1* was 
significant (P=0.0361). The overall log-likelihood sta- 
tistic for all loci among all C. opilio was significant 
(P=0.0382)(Table 5). Low-frequency alleles detected 
in Alaskan collections were AAT-1 *64, *210, and *120, 
AAT-2* 69, AH-2* 110 and *83,AH-3*106, CBYR*117, 
G3PDH-1*117, G3PDH-2*86 and *111, GPI-A1*60, 
