Page 115 - 《水产学报》2025年第8期

林悦彤，等 水产学报, 2025, 49(8): 089310

a neighbor-joining tree was constructed using using a Wilcoxon test. Correlations of shell length,
[25]
MEGA Version 11.0.13 . wet weight, byssus secretion number, plaque adhe-

sion strength, byssal breaking force, and byssal
1.3 Measurement of byssal threads parameters
thread diameter were analyzed using Spearman’s
56 mussels from each wild population were
rank correlation method. Allele frequencies of 10
evenly distributed in 7 polycarbonate tanks, each
microsatellite loci were compared according to
containing eight mussels and 10 L seawater (30
byssus secretion number, byssal thread diameter,
PSU). A plastic petri dish was placed beneath each
byssal breaking force, and plaque adhesion strength
mussel to prevent aggregation in the tank. The feed-
using the chi-square test. A P-value<0.05 was con-
ing methods were identical to those during the accli-
sidered a statistically significant difference.

mation period. After 72 hours, the byssus secretion
number was recorded, and the entire byssus was 2 RESULTS
removed from each mussel. The parameters of
byssal threads were determined using the methods 2.1 Genetic diversity
described in previous research [9,26] . Byssal thread
The analysis of genetic variation among three
diameter measurement employed an ocular micro-
populations was based on 10 microsatellite loci
meter under a stereomicroscope (SZX2, Olympus,
(Tab. 1). N observed across 10 microsatellite loci
a
Japan). The diameter of the byssus was obtained by
ranged from 3 to 13 across all the populations, but
calculating the average of the proximal, intermedi-
the numbers of alleles of all the loci were different
ate, and distal thread close to the adhesive plaque.
among the three population (Tab. 1), and each pop-
The measurements of byssal breaking force (SS:
ulation has private alleles (Tab.2). The mean values
448 threads; JJ: 217 threads; FD: 183 threads) and
of N in the SS population (7.90) were higher than
a
plaque adhesion strength (SS: 257 threads; JJ: 185
those in the JJ and FD populations (7.70 and 7.80).
threads; FD: 179 threads) were determined using a
The mean values of H ranged from 0.50 to 0.56,
o
digital force gauge mounted on a testing frame
which were lower than the mean values of H e
(HLB, Handpi, China). The byssal thread was
ranged from 0.57 to 0.62 in all populations.
clamped with iron brackets on either end to meas-
However, the H was highest in the SS population
o
ure the byssal breaking force, the corresponding
(0.44) and lowest in the FD population (0.39). The
values were recorded when stretched at a rate of 10
mean values of A ranged from 7.00 to 7.20 and the
r
mm/min until breaking. The adhesive threads within
mean values of I from 1.21 to 1.31, indicating no
Petri dishes were clamped at free end with an iron
significant loss of genetic diversity in the three wild
bracket to measure the plaque adhesive force.
populations. The PIC ranged from 0.96 to 0.97,
Byssal adhesive force was recorded when the whole
indicating high polymorphism in all three popula-
byssus had been detached from the Petri dish at a
tions (PIC>0.05). The inbreeding coefficient (F )
stretch of 10 mm/min. is

values were positive, indicating that heterozygous
1.4 Statistical analysis
deletions were present in all populations. The F in
is
JMP™ software (version 10.0.0) was used for the SS population (0.20) was lower than that in the
the analysis of the byssus parameters. The data were JJ and FD populations (0.33 and 0.40). The P in the
a
tested for normality and homogeneity using the SS population (17) was higher than that in the JJ
Shapiro-Wilk test and the O'Brien test. The differ- and FD populations (14 and 10). Except for MC44
ence in shell length, wet weight, byssus secretion loci in the SS population, nearly all the loci had
number, plaque adhesion strength, byssal breaking deviated from HWE.
force, and byssal thread diameter was analyzed The P-values of chi-square tests between
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