| 要旨トップ | 目次 | 日本生態学会第67回全国大会 (2020年3月、名古屋) 講演要旨
ESJ67 Abstract


一般講演(口頭発表) J01-02  (Oral presentation)

ミジンコ個体群の遺伝的構造はどのように形成されたか:堆積物中休眠卵の集団遺伝解析
Long-term genetic dynamics of Daphnia pulex since early establishment of population: analysis using dormant eggs preserved in lake sediment

*Yurie OTAKE(Univ. of Tokyo), Hajime OHTSUKI(Tohoku Univ.), Jotaro URABE(Tohoku Univ.), Shigeko KIMURA(Univ. of Shiga prefecture), Kazuyoshi YAMADA(Museum of Nat. & Env. Hist.), Yoshihisa SUYAMA(Tohoku Univ.), Ayumi MATSUO(Tohoku Univ.), Shun HIROTA(Tohoku Univ.), Hideki INNAN(SOKENDAI), Takehito YOSHIDA(RIHN, Univ. of Tokyo)

 How a new population establishes in a novel habitat has been an important question of ecology. Understanding the temporal change of population genetic structure is important to consider ecological and evolutionary process in establishment, although its direct observation is difficult. Here, we tried to reveal the genetic dynamics of obligate parthenogenetic Daphnia pulex population from its early establishment using their dormant eggs enclosed in ephippia preserved in the varved sediment.
 In lake Fukami-ike, Nagano, we collected lake sediment core samples and counted the ephippia to examine population dynamics. We analyzed the genetic structure based on 1628 bp of mtDNA. In addition, we measured morphological traits of ephippia and subfossils to examine the change of phenotype.
 D. pulex established a firm population in early 2000s. While we detected 13 genotypes, one genotype was dominant throughout the study period. Both of haplotype richness and diversity showed genetic structure composed by limited genotypes and suggested no trend of increasing genetic diversity. These results suggest that the priority effect and no clonal turnover was observed in this obligate parthenogenetic population. Contrary to limited genetic diversity, the morphological analysis suggested that size and time to maturity possibly changed in response to the change of predation.


日本生態学会