February 15-18, 2009 Washington State Convention Center Seattle ...

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GENETIC CHARACTERISTICS OF THREE PADDLEFISH BROODSTOCKS BASED ON
MICROSATELLITE DNA ANALYSIS
Dariusz Kaczmarczyk* and Miroslaw Luczynski
Department of Environmental Biotechnology
University of Warmia and Mazury in Olsztyn
Słoneczna 45G
10-718 Olsztyn, Poland
d.kaczmarczyk@uwm.edu.pl
The American paddlefish has been introduced into Polish aquaculture in 1995 as a species suitable for breeding in polyculture
with common carp. The paddlefish may become a popular addition to Polish fish farms, as similar attempts in neighboring
countries have been successful.
In Poland, the paddlefish is reared in two farms: Pogórze and Wąsosze. Those stocks are foreseen as source of stocking material
for future paddlefish aquaculture. Stocks of Pogórze and Wąsosze consist of small number of fish, witch originated from
the same group of parental individuals and are vulnerable to the decline heterozygosity. In this study we have examined polymorphism
at 8 microsatellite loci in Pogórze and Wąsosze and in one Ukrainian stock (Gorny Tykich) as a reference. We have
evaluated genetic variation in Polish stocks and possibility of using the Gorny Tykich stock in order to enrich genetic pool of
the Polish stocks.
DNA was extracted from fragments of fin tissues taken from all fish belonging to Polish stocks (Pogórze 24 individuals,
Wąsosze 29 individuals) and from 47 individuals belonging to Gorny Tykich stock. All fish of the Pogórze stock were tagged.
The microsatellites and surrounding sequences were amplified using PCR technique. The length of the amplified fragments
was measured using automatic DNA sequencer Beckman Coulter CEQ 8000. Measures of observed (H o ) and expected heterozygosity
(H e ), allelic richness, bottleneck effect (Garza-Williamson index) and test of departures from H-W equilibrium were
performed. The genetic divergence between populations was estimated using two different parameters: F ST and δμ 2 . Individual
genetic characteristics were developed for all individuals from Pogórze stock and have been used in estimation of theoretical
proportion of heterozygotic genotypes in the progeny of each possible male x female combination. This procedure was applied
to a single locus and then was repeated for all loci. The results were averaged and obtained value was equal to the proportion
of heterozygotic individuals in the progeny of each spawning pair.
In the investigated stocks H o ranged form 0.56 to 0.60 and H e from 0.55 to 0.61; the values were similar to those specific for
native population inhabiting Kaskasia river (Ho 0.66, He 0.63). Most microsatellite loci were in the H-W equilibrium except
most polymorphic loci such Psp 20, Psp 26 and Psp 28. The mean M – value (from 0.40 in Wąsosze; to 0.48 in Gorny Tykich)
and number of alleles (Polish and Ukrainian stocks - from 29 to 33, Kaskasia river 55) suggested that genetic variation within
the investigated stocks was reduced because of the bottleneck effect. Ukrainian stock, witch was genetically distant to Polish
stocks (F ST value from 0.54 to 0.96) could be used to enrich of the genetic pools of Polish stocks. The distance between Polish
stocks was very small (F ST 0.007), what resulted from their common origin. Heterozygosity estimated for the progeny of
particular pairs of spawners from Pogórze stock varied from 0.25 to 0.68. The progeny’s expected heterozygosity was usually
below the value specific for their parent’s generation (0.55); only few parental combinations resulted in heterozygosity higher
than 0.55. The method presented in this study could be used to maintaining the genetic variation of Polish paddlefish stock at
a present level.