Microsatellite genotype datafile for tiger sharks (Galeocerdo cuvier).

UQ eSpace ◽  
2017 ◽  
Author(s):  
Jennifer Ovenden
Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 1113-1122
Author(s):  
A F McRae ◽  
J C McEwan ◽  
K G Dodds ◽  
T Wilson ◽  
A M Crawford ◽  
...  

Abstract The last decade has seen a dramatic increase in the number of livestock QTL mapping studies. The next challenge awaiting livestock geneticists is to determine the actual genes responsible for variation of economically important traits. With the advent of high density single nucleotide polymorphism (SNP) maps, it may be possible to fine map genes by exploiting linkage disequilibrium between genes of interest and adjacent markers. However, the extent of linkage disequilibrium (LD) is generally unknown for livestock populations. In this article microsatellite genotype data are used to assess the extent of LD in two populations of domestic sheep. High levels of LD were found to extend for tens of centimorgans and declined as a function of marker distance. However, LD was also frequently observed between unlinked markers. The prospects for LD mapping in livestock appear encouraging provided that type I error can be minimized. Properties of the multiallelic LD coefficient D′ were also explored. D′ was found to be significantly related to marker heterozygosity, although the relationship did not appear to unduly influence the overall conclusions. Of potentially greater concern was the observation that D′ may be skewed when rare alleles are present. It is recommended that the statistical significance of LD is used in conjunction with coefficients such as D′ to determine the true extent of LD.


1988 ◽  
Vol 2 (4) ◽  
pp. 377-384 ◽  
Author(s):  
Mariko Miyajima ◽  
Noriaki Hamada ◽  
Etsuro Yoshimura ◽  
Akira Okubo ◽  
Sunao Yamazaki ◽  
...  

Genetics ◽  
2000 ◽  
Vol 155 (4) ◽  
pp. 1973-1980
Author(s):  
Jinko Graham ◽  
James Curran ◽  
B S Weir

Abstract Modern forensic DNA profiles are constructed using microsatellites, short tandem repeats of 2–5 bases. In the absence of genetic data on a crime-specific subpopulation, one tool for evaluating profile evidence is the match probability. The match probability is the conditional probability that a random person would have the profile of interest given that the suspect has it and that these people are different members of the same subpopulation. One issue in evaluating the match probability is population differentiation, which can induce coancestry among subpopulation members. Forensic assessments that ignore coancestry typically overstate the strength of evidence against the suspect. Theory has been developed to account for coancestry; assumptions include a steady-state population and a mutation model in which the allelic state after a mutation event is independent of the prior state. Under these assumptions, the joint allelic probabilities within a subpopulation may be approximated by the moments of a Dirichlet distribution. We investigate the adequacy of this approximation for profiled loci that mutate according to a generalized stepwise model. Simulations suggest that the Dirichlet theory can still overstate the evidence against a suspect with a common microsatellite genotype. However, Dirichlet-based estimators were less biased than the product-rule estimator, which ignores coancestry.


2017 ◽  
Vol 74 (2) ◽  
pp. 216-227 ◽  
Author(s):  
Clément Trystram ◽  
Karyne M. Rogers ◽  
Marc Soria ◽  
Sébastien Jaquemet

Stomach contents and stable carbon and nitrogen isotope analyses (δ13C and δ15N) were used to investigate the trophic ecology of two apex predators, tiger sharks (Galeocerdo cuvier) and bull sharks (Carcharhinus leucas), from Reunion Island to describe their dietary habits at both the population and individual levels. In this oceanic island, the tiger and bull sharks were more piscivorous and teutophagous than noted in previous research from other localities. The δ13C values suggested that bull sharks depended on more neritic organic matter sources than tiger sharks, confirming a coastal habitat preference for bull sharks. Moreover, the total length of the bull shark influenced δ13C values, with smaller individuals being more coastal than larger individuals. All indicators suggest that there is a higher degree of similarity between individual tiger sharks compared with the more heterogeneous bull shark population, which is composed of individuals who specialize on different prey. These results suggest that the two species have different functions in these coastal habitats, and thus, they must be considered independently in terms of conservation and management.


2016 ◽  
Vol 43 (1) ◽  
pp. 165-178 ◽  
Author(s):  
Natascha Wosnick ◽  
Hugo Bornatowski ◽  
Carolina Ferraz ◽  
André Afonso ◽  
Bianca Sousa Rangel ◽  
...  

2021 ◽  
Author(s):  
Alice Manuzzi ◽  
Belen Jiménez-Mena ◽  
Romina Henriques ◽  
Bonnie J. Holmes ◽  
Julian Pepperell ◽  
...  

Abstract Over the last century, many populations of sharks have been reduced in numbers by overexploitation or attempts to mitigate human-shark interactions. Still, there is a general perception that populations of large ocean predators cover wide areas and therefore their diversity is less susceptible to local anthropogenic disturbance. Here we report retrospective genomic analyses of DNA using archived and contemporary samples of tiger shark (Galeocerdo cuvier) from eastern Australia. Using SNP loci, we documented a significant overall change in genetic composition of tiger sharks born over the last century. The change was most likely due to a shift over time in the relative contribution of two well differentiated, but hitherto cryptic populations. Our data strongly indicate a dramatic shift in relative contribution of the two populations to the overall tiger shark abundance of the east coast of Australia, possibly associated with differences in direct or indirect exploitation rates.


2022 ◽  
Author(s):  
Neil Hammerschlag ◽  
Laura H. McDonnell ◽  
Mitchell J. Rider ◽  
Garrett M. Street ◽  
Elliott L. Hazen ◽  
...  

2012 ◽  
Vol 63 (11) ◽  
pp. 1069 ◽  
Author(s):  
Aaron J. Wirsing ◽  
Michael R. Heithaus

Although not widely appreciated, prey can manage predation risk by modifying the sequence of their behavioural states. We explored this phenomenon in dugongs (Dugong dugon) subject to spatially and temporally variable risk of tiger shark (Galeocerdo cuvier) predation in Shark Bay, Australia. Dugong behaviour was assayed using focal follows and organised into sequences of foraging, resting, and travelling bouts. We used log-linear analysis to test for sequence differences in relation to habitat (deep, shallow) and predation danger (sharks present, largely absent). Dugongs modified their behavioural sequences between periods of high and low shark abundance: those at risk alternated more frequently between foraging, which constrains anti-predator vigilance, and travelling, which facilitates predator detection. Dugongs also avoided continuous series of resting bouts, during which awareness is reduced, when sharks were present. These changes were only observed in relatively dangerous shallow habitat, which is hunted disproportionately by tiger sharks; behavioural responses to sharks in deep habitat were modest. We conclude that dugongs in risky habitat resort to safer behavioural sequences in response to sharks. Given that human disturbance and predators are perceived similarly by many species, some forms of vessel interaction could compromise the fitness of sirenians by eliciting similar behavioural adjustment.


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