Nuclear and mitochondrial DNA markers indicate unidirectional gene flow of Indo-Pacific to Atlantic bigeye tuna (Thunnus obesus) populations, and their admixture off southern Africa

2005 ◽  
Vol 147 (2) ◽  
pp. 313-322 ◽  
Author(s):  
J.-D. Durand ◽  
A. Collet ◽  
S. Chow ◽  
B. Guinand ◽  
P. Borsa
Keyword(s):  
Mitochondrial Dna ◽  
Gene Flow ◽  
Southern Africa ◽  
Dna Markers ◽  
Bigeye Tuna ◽  
Thunnus Obesus

Strong population structure and limited gene flow between Yellow-billed Ducks and Mallards in southern Africa

The Condor ◽  
2019 ◽  
Author(s):  
Joshua I Brown ◽  
Philip Lavretsky ◽  
Graeme S Cumming ◽  
Jeffrey L Peters
Keyword(s):  
Mitochondrial Dna ◽  
Gene Flow ◽  
Southern Africa ◽  
Secondary Contact ◽  
Nuclear Markers ◽  
Nuclear Introns ◽  
Contemporary Gene Flow ◽  
Limited Gene Flow ◽  
Genetic Swamping ◽  
Evolutionary Consequences

AbstractSecondary contact and hybridization between recently diverged taxa have been increasing due to anthropogenic changes to the environment. Determining whether secondary contact leads to gene flow between species is important for understanding both the evolutionary consequences of such events (i.e. genetic swamping, speciation reversal, hybrid speciation) and for establishing proper conservation measures. Mallards (Anas platyrhynchos), which natively have a Holarctic distribution, have been introduced nearly worldwide due to game-farm and domestic pet releases. Their expanding range has resulted in secondary contact and increased incidences of hybridization with many closely related Mallard-like ducks that comprise the Mallard complex. Here, we assay molecular diversity for 19 nuclear introns and the mitochondrial DNA for wild Mallards (n = 50) across their Holarctic range and Yellow-billed Ducks (n = 30–75; Anas undulata) from southern Africa to determine population genetic structure and test for evidence of Mallard introgression into Yellow-billed Ducks. While we found limited support for contemporary gene flow across nuclear markers, we provide evidence from mitochondrial DNA that best supports ancient gene flow between Yellow-billed Ducks and Mallards. Yellow-billed Ducks best fit a single population at nuclear markers but show some location-specific mtDNA structure that suggests recent founder or bottleneck events. Although we find that introgression from Mallards into Yellow-billed Duck is limited, Yellow-billed Duck populations should be monitored to determine if expanding feral Mallard populations in southern Africa are increasing introgression.

scholarly journals Population structure of bigeye tuna (Thunnus obesus) in the Indian Ocean inferred from mitochondrial DNA

2008 ◽  
Vol 90 (1-3) ◽  
pp. 305-312 ◽  
Author(s):  
Hsin-Chieh Chiang ◽  
Chien-Chung Hsu ◽  
Georgiana Cho-Chen Wu ◽  
Shui-Kai Chang ◽  
Hsi-Yuan Yang
Keyword(s):  
Mitochondrial Dna ◽  
Population Structure ◽  
Indian Ocean ◽  
Bigeye Tuna ◽  
Thunnus Obesus ◽  
The Indian Ocean

QUANTIFICATION OF TUNA FISH TARGET STRENGTH USING QUANTITATIVE ECHO SOUNDER

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Henry M. Manik
Keyword(s):  
Wave Reflection ◽  
Fork Length ◽  
Research Programme ◽  
Yellowfin Tuna ◽  
Target Strength ◽  
Bigeye Tuna ◽  
Tuna Fish ◽  
Thunnus Obesus ◽  
The Relationship ◽  
Echo Sounder

A preliminary research programme was carried out in order to study the acoustic wave reflection or target strength (TS) of tuna fish using a quantitative echo sounder (QES). The relationships between TS to fork length (FL) and swimbladder volume, for bigeye tuna (Thunnus obesus) and yellowfin tuna (T. albacares) are investigated. The TS of bigeye tuna was about 3 dB higher than yellowfin tuna when comparing species at the same size. The result can be correlated to the swimbladder volume differencebetween species. The relationship between TS and swimbladder volume was quantified for both species.Keywords: tuna fish, target strength, quantitative echo sounder

Vertical distribution of bigeye tuna Thunnus obesus in the tropical Indian Ocean

2013 ◽  
Vol 20 (3) ◽  
pp. 660-671 ◽  
Author(s):  
Xuezhong CHEN ◽  
Shenglong YANG ◽  
Yu Zhang ◽  
Wei FAN ◽  
Yumei WU
Keyword(s):  
Indian Ocean ◽  
Vertical Distribution ◽  
Tropical Indian Ocean ◽  
Bigeye Tuna ◽  
Thunnus Obesus

scholarly journals First Insight into Groundwater Copepods of the Polish Lowland

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2086
Author(s):  
Maciej Karpowicz ◽  
Sabina Smolska ◽  
Magdalena Świsłocka ◽  
Joanna Moroz
Keyword(s):  
Mitochondrial Dna ◽  
Ribosomal Rna ◽  
Dna Markers ◽  
Coi Gene ◽  
Molecular Characteristics ◽  
Morphological Description ◽  
Single Plate ◽  
North Eastern ◽  
Insight Into

Our results are the first insight into groundwater copepods of the Polish Lowland. The sampling was conducted in 28 wells in north-eastern Poland, and Copepoda were present in 16 wells. We have identified six Copepoda species and one Cladocera. We have classified four species as stygophiles—Eucyclops serrulatus, Diacyclops bisetosus, Diacyclops crassicaudis, and Cyclops furcifer. These species were frequently found in studied wells of different regions of north-eastern Poland, often in high numbers, and females with egg sacs were observed. We present a detailed morphological description of these species, together with molecular characteristics based on mitochondrial DNA markers (COI gene) for E. serrulatus, D. bisetosus, and D. crassicaudis, and 12S ribosomal RNA for C. furcifer. We also present the development of abnormal structures in one specimen of D. crassicaudis, where the upper part of furcal rami was fused to form a single plate.

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