Limited Genetic Diversity Preceded Extinction of the Tasmanian Tiger

The Tasmanian tiger or thylacine was the largest carnivorous marsupial when Europeans first reached Australia. Sadly, the last known thylacine died in captivity in 1936. A recent analysis of the genome of the closely related and extant Tasmanian devil demonstrated limited genetic diversity between individuals. While a similar lack of diversity has been reported for the thylacine, this analysis was based on just two individuals. Here we report the sequencing of an additional 12 museum-archived specimens collected between 102 and 159 years ago. We examined a portion of the mitochondrial DNA hyper-variable control region and determined that all sequences were on average 99.5% identical at the nucleotide level. As a measure of accuracy we also sequenced mitochondrial DNA from a mother and two offspring. As expected, these samples were found to be 100% identical, validating our methods. We also used 454 sequencing to reconstruct 2.1 kilobases of the mitochondrial genome, which shared 99.91% identity with the two complete thylacine mitochondrial genomes published previously. Our thylacine genomic data also contained three highly divergent putative nuclear mitochondrial sequences, which grouped phylogenetically with the published thylacine mitochondrial homologs but contained 100-fold more polymorphisms than the conserved fragments. Together, our data suggest that the thylacine population in Tasmania had limited genetic diversity prior to its extinction, possibly as a result of their geographic isolation from mainland Australia approximately 10,000 years ago

A Neuropsychological Profile of College Students with Attention Deficit Hyperactivity Disorder

Large scale studies of Attention Deficit Hyperactivity Disorder (ADHD) have found that in about 40% of children with a diagnosis, symptoms continue well into adulthood. This poor prognosis makes it imperative that adult ADHD become better understood at the neuropsychological level so novel therapies and diagnostic practices can be established. The purpose of the present study was to examine neuropsychological traits in college students with and without ADHD as well as compare different measures for assessment. Students (N=368) were recruited from a southeastern, large public university across the Fall semester of 2020 to complete an online survey. The survey included screeners for ADHD such as the Adult ADHD Self-Report Scale (ASRSv1.1), depression (PHQ-8), anxiety (GAD-7), and stress (PSS-10). The average age of participants was 18.69, with the majority being female (68.2%), White (72%), and freshman (76.9). Students were sorted into an ADHD group (n=100) and control group (n=268) depending on diagnostic history and scores on the ASRSv.1.1. A smaller subset of those participants (n=27 for ADHD group, n=19 for control group) were asked to complete an evaluation of neuropsychological functioning as per the CogniFit’s Cognitive Assessment Battery and the Brown Executive Function/Attention Scales (Brown EF-A), and an assessment of ADHD symptom severity with the Conners’ Adult ADHD Rating Scale (CAARS). Comparisons of each neuropsychological domain between ADHD and control groups were conducted using multivariate analyses of variance. Scores on the Brown EF-A were significantly higher (p<.001) for the ADHD group compared to the Control across all domains. A MANOVA for CogniFit revealed significant difference between those and without ADHD. Pearson correlations showed strong correlations between neuropsychological functioning (Brown EF-A and CogniFit) and scores on the CAARS and the ASRS. Chi-square tests revealed significant differences between the Brown EF-A, CAARS, and ASRS for positive screening of participants for ADHD. Lastly, individuals with ADHD had significantly higher psychological symptomatology across depression and anxiety. Results from this study show a need for more consistent, accurate diagnostic practices of Adult ADHD and builds the framework for the creation of targeted interventions to address neuropsychological deficits

MHC gene copy number variation in Tasmanian devils: implications for the spread of a contagious cancer

Tasmanian devils face extinction owing to the emergence of a contagious cancer. Devil facial tumour disease (DFTD) is a clonal cancer spread owing to a lack of major histocompatibility complex (MHC) barriers in Tasmanian devil populations. We present a comprehensive screen of MHC diversity in devils and identify 25 MHC types and 53 novel sequences, but conclude that overall levels of MHC diversity at the sequence level are low. The majority of MHC Class I variation can be explained by allelic copy number variation with two to seven sequence variants identified per individual. MHC sequences are divided into two distinct groups based on sequence similarity. DFTD cells and most devils have sequences from both groups. Twenty per cent of individuals have a restricted MHC repertoire and contain only group I or only group II sequences. Counterintuitively, we postulate that the immune system of individuals with a restricted MHC repertoire may recognize foreign MHC antigens on the surface of the DFTD cell. The implication of these results for management of DFTD and this endangered species are discussed

Supplement to a list of the crustacea of Tasmania

Volume: 5Start Page: 1End Page:

Notes on Tasmanian marine sponges

Volume: 3Start Page: 5End Page: 1

A list of the Crustacea of Tasmania

Volume: 3Start Page: 15End Page: 4

A Neuropsychological Profile of College Students with Attention Deficit Hyperactivity Disorder

Large scale studies of Attention Deficit Hyperactivity Disorder (ADHD) have found that in about 40% of children with a diagnosis, symptoms continue well into adulthood. This poor prognosis makes it imperative that adult ADHD become better understood at the neuropsychological level so novel therapies and diagnostic practices can be established. The purpose of the present study was to examine neuropsychological traits in college students with and without ADHD as well as compare different measures for assessment. Students (N=368) were recruited from a southeastern, large public university across the Fall semester of 2020 to complete an online survey. The survey included screeners for ADHD such as the Adult ADHD Self-Report Scale (ASRSv1.1), depression (PHQ-8), anxiety (GAD-7), and stress (PSS-10). The average age of participants was 18.69, with the majority being female (68.2%), White (72%), and freshman (76.9). Students were sorted into an ADHD group (n=100) and control group (n=268) depending on diagnostic history and scores on the ASRSv.1.1. A smaller subset of those participants (n=27 for ADHD group, n=19 for control group) were asked to complete an evaluation of neuropsychological functioning as per the CogniFit’s Cognitive Assessment Battery and the Brown Executive Function/Attention Scales (Brown EF-A), and an assessment of ADHD symptom severity with the Conners’ Adult ADHD Rating Scale (CAARS). Comparisons of each neuropsychological domain between ADHD and control groups were conducted using multivariate analyses of variance. Scores on the Brown EF-A were significantly higher (p&lt;.001) for the ADHD group compared to the Control across all domains. A MANOVA for CogniFit revealed significant difference between those and without ADHD. Pearson correlations showed strong correlations between neuropsychological functioning (Brown EF-A and CogniFit) and scores on the CAARS and the ASRS. Chi-square tests revealed significant differences between the Brown EF-A, CAARS, and ASRS for positive screening of participants for ADHD. Lastly, individuals with ADHD had significantly higher psychological symptomatology across depression and anxiety. Results from this study show a need for more consistent, accurate diagnostic practices of Adult ADHD and builds the framework for the creation of targeted interventions to address neuropsychological deficits