TY - JOUR
T1 - Significant loss of genetic diversity and accumulation of deleterious genetic variation in a critically endangered azalea species, Rhododendron boninense, growing on the Bonin Islands
AU - Isagi, Yuji
AU - Makino, Takashi
AU - Hamabata, Tomoko
AU - Cao, Ping Lin
AU - Narita, Satoshi
AU - Komaki, Yoshiteru
AU - Kurita, Kazuki
AU - Naiki, Akiyo
AU - Kameyama, Yoshiaki
AU - Kondo, Toshiaki
AU - Shibabayashi, Mayu
N1 - Funding Information:
This research was supported by the Environment Research and Technology Development Fund (4‐1605 and 4‐1902) from the Environmental Restoration and Conservation Agency, Japan, and Grant‐in‐Aid for Scientific Research (KAKENHI) (Grant Numbers 15H04414, 17H0467 and 18H02496) from the Japan Society for the Promotion of Science. Some computations were performed on the supercomputer at the Research Organization of Information and Systems, National Institute of Genetics.
Funding Information:
This research was supported by the Environment Research and Technology Development Fund (4-1605 and 4-1902) from the Environmental Restoration and Conservation Agency, Japan, and Grant-in-Aid for Scientific Research (KAKENHI) (Grant Numbers 15H04414, 17H0467 and 18H02496) from the Japan Society for the Promotion of Science. Some computations were performed on the supercomputer at the Research Organization of Information and Systems, National Institute of Genetics.
Publisher Copyright:
© 2020 The Society for the Study of Species Biology
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Loss of genetic diversity increases the risk of extinction of a population through inbreeding depression. In addition, the number of deleterious genetic variations, which might accumulate in a small population through genetic drift, can also make the population vulnerable. Rhododendron boninense is a critically endangered azalea species, which grows on the Bonin Islands, a UNESCO World Heritage Site; its population size in the wild dropped to only a single individual. Although a governmental program for species conservation has been conducted, no successful natural regeneration or population growth was achieved. We hypothesized that the reduced genetic diversity and accumulated deleterious genetic variation might cause the vulnerability of the species, and conducted comparative genetic and genomic analyses between R. boninense and its congeners. Genetic analysis using microsatellite markers indicated that the genetic diversity of R. boninense was ultimately low; microsatellite loci of this species were all fixed, whereas the congeners maintain high allelic diversity. Based on comprehensive transcriptome analysis, the amount of deleterious variation of R. boninense was significantly greater than that of R. amanoi. Repeated generation transitions of the small population of R. boninense on the oceanic islands is likely to have resulted in low genetic diversity as well as more deleterious variations in the genome, and we speculated that the accumulated deleterious variation might result in vulnerability of R. boninense. This study indicates the possibility of evaluating the feasibility of effective conservation programs based on the genetic diversity and the amount of accumulated deleterious variation in the genome of critically endangered species.
AB - Loss of genetic diversity increases the risk of extinction of a population through inbreeding depression. In addition, the number of deleterious genetic variations, which might accumulate in a small population through genetic drift, can also make the population vulnerable. Rhododendron boninense is a critically endangered azalea species, which grows on the Bonin Islands, a UNESCO World Heritage Site; its population size in the wild dropped to only a single individual. Although a governmental program for species conservation has been conducted, no successful natural regeneration or population growth was achieved. We hypothesized that the reduced genetic diversity and accumulated deleterious genetic variation might cause the vulnerability of the species, and conducted comparative genetic and genomic analyses between R. boninense and its congeners. Genetic analysis using microsatellite markers indicated that the genetic diversity of R. boninense was ultimately low; microsatellite loci of this species were all fixed, whereas the congeners maintain high allelic diversity. Based on comprehensive transcriptome analysis, the amount of deleterious variation of R. boninense was significantly greater than that of R. amanoi. Repeated generation transitions of the small population of R. boninense on the oceanic islands is likely to have resulted in low genetic diversity as well as more deleterious variations in the genome, and we speculated that the accumulated deleterious variation might result in vulnerability of R. boninense. This study indicates the possibility of evaluating the feasibility of effective conservation programs based on the genetic diversity and the amount of accumulated deleterious variation in the genome of critically endangered species.
KW - PROVEAN
KW - RNA-seq
KW - critically endangered species
KW - deleterious variation
KW - genetic diversity
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U2 - 10.1111/1442-1984.12270
DO - 10.1111/1442-1984.12270
M3 - Article
AN - SCOPUS:85082928263
VL - 35
SP - 166
EP - 174
JO - Plant Species Biology
JF - Plant Species Biology
SN - 0913-557X
IS - 3
ER -