scholarly journals An Investigation into the Genetic History of Japanese Populations of Three Starfish, Acanthaster planci, Linckia laevigata, and Asterias amurensis, Based on Complete Mitochondrial DNA Sequences

2020 ◽  
Vol 10 (7) ◽  
pp. 2519-2528 ◽  
Author(s):  
Jun Inoue ◽  
Kanako Hisata ◽  
Nina Yasuda ◽  
Noriyuki Satoh
Keyword(s):  
Population Genetics ◽  
Mitochondrial Dna ◽  
Coral Reefs ◽  
Dna Sequences ◽  
Ryukyu Archipelago ◽  
Acanthaster Planci ◽  
Asterias Amurensis ◽  
Okinawa Island ◽  
Ishigaki Island ◽  
Linckia Laevigata

Crown-of-thorns starfish, Acanthaster planci (COTS), are common in coral reefs of Indo-Pacific Ocean. Since they are highly fecund predators of corals, periodic outbreaks of COTS cause substantial loss of healthy coral reefs. Using complete mitochondrial DNA sequences, we here examined how COTS outbreaks in the Ryukyu Archipelago, Japan are reflected by the profile of their population genetics. Population genetics of the blue starfish, Linckia laevigata, which lives in the Ryukyu Archipelago, but not break out and the northern Pacific sea star, Asterias amurensis, which lives in colder seawater around the main Islands of Japan, were also examined as controls. Our results showed that As. amurensis has at least two local populations that diverged approximately 4.7 million years ago (MYA), and no genetic exchanges have occurred between the populations since then. Linckia laevigata shows two major populations in the Ryukyu Archipelago that likely diverged ∼6.8 MYA. The two populations, each comprised of individuals collected from coast of the Okinawa Island and those from the Ishigaki Island, suggest the presence of two cryptic species in the Ryukyu Archipelago. On the other hand, population genetics of COTS showed a profile quite different from those of Asterias and Linckia. At least five lineages of COTS have arisen since their divergence ∼0.7 MYA, and each of the lineages is present at the Okinawa Island, Miyako Island, and Ishigaki Island. These results suggest that COTS have experienced repeated genetic bottlenecks that may be associated with or caused by repeated outbreaks.

Himaloconnus Franz and Nogunius gen. n. of Japan (Coleoptera: Staphylinidae: Scydmaeninae)

Zootaxa ◽  
2020 ◽  
Vol 4822 (3) ◽  
pp. 334-360
Author(s):  
PAWEŁ JAŁOSZYŃSKI
Keyword(s):  
Identification Key ◽  
Ryukyu Archipelago ◽  
Okinawa Island ◽  
New Subspecies ◽  
Ishigaki Island ◽  
Morphological Differences ◽  
Izu Islands

Two genera of Euconnus-like Stenichnini are reported to occur in Japan: Himaloconnus Franz, 1979 and Nogunius gen. n. Specimens of Himaloconnus collected on islands of the Ryukyu archipelago are identified as H. klapperichianus (Franz), previously known to inhabit Taiwan, but morphological differences were found among disjunctive populations and in consequence three new subspecies are proposed: H. klapperichianus yaeyamanus ssp. n. (Yaeyama Islands), H. klapperichianus amamianus ssp. n. (Amami-Ôshima), and H. klapperichianus okinawanus ssp. n. (Okinawa Island). Morphological structures of Japanese Himaloconnus are illustrated in detail and the diagnosis of this genus is emended, to exclude variable characters. Nogunius gen. n. is established to accommodate four species known only from Japan: N. sokani sp. n. (Okinawa Island), N. aogashimanus sp. n. (Aogashima, Izu Islands), N. kerri sp. n. (Ishigaki Island), and N. fukuuzanus sp. n. (Okinawa Island). Identification key to Japanese genera of Stenichnini is updated. 

scholarly journals Pairwise comparisons of mitochondrial DNA sequences in subdivided populations and implications for early human evolution.

Genetics ◽  
1994 ◽  
Vol 136 (2) ◽  
pp. 673-683 ◽  
Author(s):  
P Marjoram ◽  
P Donnelly
Keyword(s):  
Population Genetics ◽  
Mitochondrial Dna ◽  
Dna Sequences ◽  
Human Populations ◽  
Human Mitochondrial Dna ◽  
Multimodal Distributions ◽  
Subdivided Populations ◽  
Migration Dynamics ◽  
Pairwise Differences ◽  
Mutation Mechanisms

Abstract We consider the effect on the distribution of pairwise differences between mitochondrial DNA sequences of the incorporation into the underlying population genetics model of two particular effects that seem realistic for human populations. The first is that the population size was roughly constant before growing to its current level. The second is that the population is geographically subdivided rather than panmictic. In each case these features tend to encourage multimodal distributions of pairwise differences, in contrast to existing, unimodal datasets. We argue that population genetics models currently used to analyze such data may thus fail to reflect important features of human mitochondrial DNA evolution. These may include selection on the mitochondrial genome, more realistic mutation mechanisms, or special population or migration dynamics. Particularly in view of the variability inherent in the single available human mitochondrial genealogy, it is argued that until these effects are better understood, inferences from such data should be rather cautious.

Supplementary descriptions of Pergalumna amamiensis Aoki, 1984 (Acariformes, Galumnoidea) from Ryukyu Islands

Zootaxa ◽  
2019 ◽  
Vol 4647 (1) ◽  
pp. 378-384
Author(s):  
WATARU HAGINO ◽  
SATOSHI SHIMANO
Keyword(s):  
Body Length ◽  
Morphological Traits ◽  
Granular Structure ◽  
Surface Pattern ◽  
Ryukyu Islands ◽  
Body Width ◽  
Okinawa Island ◽  
Ishigaki Island ◽  
Circular Surface ◽  
Median Pore

A species of oribatid mites, Pergalumna amamiensis was collected from Amami-Ohshima Island, Ishigaki Island, and Okinawa Island, Southwestern Japan. The specimens were studied in detail, and supplementary descriptions are provided; these include features of the rostrum, the subcapitulum and the surface pattern of pteromorphs. The main morphological traits for this species are summarized as follows; body length 519–570 μm, body width 363–410 μm, rostral tip pointed, sensillus with a long stalk covered by minute barbs, porose areas Aa bulbous, porose areas A1, A2, and A3 circular, surface of pteromorphs ornamented by fine granular structure and dense wrinkles, fine granular structure on prodorsum, subcapitulum, genital plates and anal plates, median pore on the notogaster represented as single pore. 

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