Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 5 de 5
Filter
Add more filters










Database
Language
Publication year range
1.
Heredity (Edinb) ; 122(1): 53-68, 2019 01.
Article in English | MEDLINE | ID: mdl-29720718

ABSTRACT

Understanding how dispersal and gene flow link geographically separated the populations over evolutionary history is challenging, particularly in migratory marine species. In southern right whales (SRWs, Eubalaena australis), patterns of genetic diversity are likely influenced by the glacial climate cycle and recent history of whaling. Here we use a dataset of mitochondrial DNA (mtDNA) sequences (n = 1327) and nuclear markers (17 microsatellite loci, n = 222) from major wintering grounds to investigate circumpolar population structure, historical demography and effective population size. Analyses of nuclear genetic variation identify two population clusters that correspond to the South Atlantic and Indo-Pacific ocean basins that have similar effective breeder estimates. In contrast, all wintering grounds show significant differentiation for mtDNA, but no sex-biased dispersal was detected using the microsatellite genotypes. An approximate Bayesian computation (ABC) approach with microsatellite markers compared the scenarios with gene flow through time, or isolation and secondary contact between ocean basins, while modelling declines in abundance linked to whaling. Secondary-contact scenarios yield the highest posterior probabilities, implying that populations in different ocean basins were largely isolated and came into secondary contact within the last 25,000 years, but the role of whaling in changes in genetic diversity and gene flow over recent generations could not be resolved. We hypothesise that these findings are driven by factors that promote isolation, such as female philopatry, and factors that could promote dispersal, such as oceanographic changes. These findings highlight the application of ABC approaches to infer the connectivity in mobile species with complex population histories and, currently, low levels of differentiation.


Subject(s)
Evolution, Molecular , Genetic Variation/genetics , Genetics, Population , Whales/genetics , Animals , Climate , DNA, Mitochondrial/genetics , Gene Flow/genetics , Genotype , Haplotypes/genetics , Microsatellite Repeats/genetics , Pacific Ocean , Phylogeny , Population Density , Whales/physiology
2.
PLoS One ; 11(1): e0146590, 2016.
Article in English | MEDLINE | ID: mdl-26751689

ABSTRACT

Juvenile survival and recruitment can be more sensitive to environmental, ecological and anthropogenic factors than adult survival, influencing population-level processes like recruitment and growth rate in long-lived, iteroparous species such as southern right whales. Conventionally, Southern right whales are individually identified using callosity patterns, which do not stabilise until 6-12 months, by which time the whale has left its natal wintering grounds. Here we use DNA profiling of skin biopsy samples to identify individual Southern right whales from year of birth and document their return to the species' primary wintering ground in New Zealand waters, the Subantarctic Auckland Islands. We find evidence of natal fidelity to the New Zealand wintering ground by the recapture of 15 of 57 whales, first sampled in year of birth and available for subsequent recapture, during winter surveys to the Auckland Islands in 1995-1998 and 2006-2009. Four individuals were recaptured at the ages of 9 to 11, including two females first sampled as calves in 1998 and subsequently resampled as cows with calves in 2007. Using these capture-recapture records of known-age individuals, we estimate changes in survival with age using Cormack-Jolly-Seber models. Survival is modelled using discrete age classes and as a continuous function of age. Using a bootstrap method to account for uncertainty in model selection and fitting, we provide the first direct estimate of juvenile survival for this population. Our analyses indicate a high annual apparent survival for juveniles at between 0.87 (standard error (SE) 0.17, to age 1) and 0.95 (SE 0.05: ages 2-8). Individual identification by DNA profiling is an effective method for long-term demographic and genetic monitoring, particularly in animals that change identifiable features as they develop or experience tag loss over time.


Subject(s)
Animal Migration , Whales/physiology , Animals , Biopsy , Female , Genetic Variation , Genotype , Geography , Male , New Zealand , Population Density , Population Dynamics , Seasons , Sequence Analysis, DNA , Skin , Whales/growth & development
3.
Ecol Appl ; 23(7): 1677-90, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24261048

ABSTRACT

Superpopulation capture-recapture models are useful for estimating the abundance of long-lived, migratory species because they are able to account for the fluid nature of annual residency at migratory destinations. Here we extend the superpopulation POPAN model to explicitly account for heterogeneity in capture probability linked to reproductive cycles (POPAN-tau). This extension has potential application to a range of species that have temporally variable life stages (e.g., non-annual breeders such as albatrosses and baleen whales) and results in a significant reduction in bias over the standard POPAN model. We demonstrate the utility of this model in simultaneously estimating abundance and annual population growth rate (lamda) in the New Zealand (NZ) southern right whale (Eubalaena australis) from 1995 to 2009. DNA profiles were constructed for the individual identification of more than 700 whales, sampled during two sets of winter expeditions in 1995-1998 and 2006-2009. Due to differences in recapture rates between sexes, only sex-specific models were considered. The POPAN-tau models, which explicitly account for a decrease in capture probability in non-calving years, fit the female data set significantly better than do standard superpopulation models (deltaAIC > 25). The best POPAN-tau model (AIC) gave a super-population estimate of 1162 females for 1995-2009 (95% CL 921, 1467) and an estimated annual increase of 5% (95% CL--2%, 13%). The best model (AIC) gave a superpopulation estimate of 1007 males (95% CL 794, 1276) and an estimated annual increase of 7% (95% CL 5%, 9%) for 1995-2009. Combined, the total superpopulation estimate for 1995-2009 was 2169 whales (95% CL 1836, 2563). Simulations suggest that failure to account for the effect of reproductive status on the capture probability would result in a substantial positive bias (+19%) in female abundance estimates.


Subject(s)
Reproduction/physiology , Whales/physiology , Animals , Female , Genotype , Male , Models, Biological , Population Density , Whales/genetics
4.
J Hand Ther ; 22(1): 21-6; quiz 27, 2009.
Article in English | MEDLINE | ID: mdl-18986794

ABSTRACT

STUDY DESIGN: Longitudinal Case Series. INTRODUCTION: Dupytren's contracture is thought to result in digital impairments and performance disabilities. No study to date has focused on how patients with Dupuytren's contracture experience limitations in daily activities and the results after surgery. PURPOSE OF THE STUDY: Describe which activities patients with Dupuytren's contracture defined as the most disabling, how they rated their activity limitations and determine the relationship between activity limitations and digital extension before and three months after surgery and postoperative hand therapy. METHODS: Self-reported rating of activity limitations, performance, and measures of total digital extension. RESULTS: The most disabling activities were with self-care (42%), though overall performance was significantly improved following surgery and postoperative hand therapy. The total digital extension was significantly improved 81 degrees and was positively related to performance. CONCLUSIONS: The results provide new information about activities that patients with Dupuytren's contracture experience as being difficult to perform and describes positive changes in performance and range of motion. LEVEL OF EVIDENCE: 4.


Subject(s)
Activities of Daily Living , Disability Evaluation , Dupuytren Contracture/physiopathology , Dupuytren Contracture/therapy , Adult , Aged , Aged, 80 and over , Fasciotomy , Female , Humans , Longitudinal Studies , Male , Middle Aged , Physical Therapy Modalities , Range of Motion, Articular/physiology , Self Care
SELECTION OF CITATIONS
SEARCH DETAIL
...