Study of genetic variability in the wildlife (Hokkaido brown bear)

点击翻译按钮获取中文摘要

1.Semen collection and cryopreservation of spermatozoa in Hokkaido brown bear(1) Semen collection was succes using electroejaculation in Hokkaido brown bear. The obtained ejaculates provided baseline data of bear semen, such as ejaculate volume. sperm concentration, sperm motility, and sperm abnormality rate.(2) The study of freezing technique for bear semen using Tris-buffered egg yolk extender provided the optimal condition, such as final glycerol concentration, equilibration period, and cooling rate. The characteristics of post-thaw semen showed that the mean sperm motility and the mean percentage of live spermatozoa of post-thaw semen were 36.0% and 65.0%, respectively.(3) Annual changes in serum testosterone concentration, serum FSH concentration and seminal traits were investigated. The increase in serum testosterone concentration was followed by the increases of sperm concentration. The pattern of the annual change of serum FSH concentration was similar to that in testis volume.2.Genetic variability of Hokkaido brown bear(1) About 300 liver samples for DNA research were collected at the Hokkaido Institute of Environmental Science.(2) The effort of searching microsatellite region is maintained, though any individually variable microsatellite region has not been detected. Eight previously developed primer sets for microsatellites of another bear species were applied to 54 captive Hokkaido brown bears. As the result, 4 to 10 (6.5+1.9) alleles were detected, and the average heterozygosity (gene diversity) was 0.67+0.12. These values are similar to those of another bear species and may suggest that the applied primer sets were thought to be effective for evaluating the genetic variability of Hokkaido brown bears. At present, analysis of DNA samples extracted from wild bears is doing with those primer sets.(3) The same research as Hokkaido brown bear with those 8 primer sets are performing about the Japanese black bear.