Resolving the phylogenetic relationship among recently diverged members of the rockfish subgenus Sebastosomus.

Rapid speciation is an important aspect of adaptive radiations, but can obfuscate phylogenetic relationships among taxa. For recent radiations, there are challenges to reconstructing the relationships among the species due to often shorter branch lengths. Resolution of these relationships is further confounded when studies only use a few genetic markers. Double digest restriction-site associated DNA sequencing (ddRADseq) is a method of next generation sequencing that identifies many single nucleotide polymorphisms (SNPs) throughout the genome. This increases statistical power to resolve close phylogenetic relationships like those found within an adaptive radiation. We used this approach to understand the evolutionary history of the rockfishes of the genus Sebastes, which experienced an adaptive radiation between 3 and 5 mya. Here, we reconstructed the phylogenetic relationships among six species of rockfish within the subgenus Sebastosomus using over 11,600 SNPs. This reconstruction includes the two recently diverged species, Sebastes mystinus and S. diaconus, that were first described genetically in 2008 using mtDNA control region sequence data and six microsatellite loci. We confirmed the relationship of these cryptic species as sister-taxa and found evidence that S. melanops and S. flavidus were also sister-taxa. The latter contradicts prior studies but is supported by our reconstruction using nuclear DNA and measures of genetic differentiation tests and a discriminant analysis of principal components. The relationships between the species of Sebastosomus are further supported by morphological, biological, and ecological justifications.

Gridlock and beltways: the genetic context of urban invasions.

The rapid expansion of urban land across the globe presents new and numerous opportunities for invasive species to spread and flourish. Ecologists historically rejected urban ecosystems as important environments for ecology and evolution research but are beginning to recognize the importance of these systems in shaping the biology of invasion. Urbanization can aid the introduction, establishment, and spread of invaders, and these processes have substantial consequences on native species and ecosystems. Therefore, it is valuable to understand how urban areas influence populations at all stages in the invasion process. Population genetic tools are essential to explore the driving forces of invasive species dispersal, connectivity, and adaptation within cities. In this review, we synthesize current research about the influence of urban landscapes on invasion genetics dynamics. We conclude that urban areas are not only points of entry for many invasive species, they also facilitate population establishment, are pools for genetic diversity, and provide corridors for further spread both within and out of cities. We recommend the continued use of genetic studies to inform invasive species management and to understand the underlying ecological and evolutionary processes governing successful invasion.

Oliguria during hydrocortisone dosage wean in very low birth weight infants.

BACKGROUND: Intravenous hydrocortisone (HC) is often used in very low birth weight infants (VLBW) but can be complicated by oliguria when discontinued or tapered. OBJECTIVES: To determine which factors were associated with oliguria during HC taper. METHODS: We reviewed all VLBW infants who received initial doses of HC ≥ 1 mg/kg/d. The initial dose and duration of HC, and the incidence of oliguria (urine output [UO] < 2 mL/kg/h) during HC taper, were recorded. In those with oliguria, we recorded the change in UO (mL/kg/h), blood pressure, and creatinine. RESULTS: The mean initial HC dose was 2.8 ± 1 mg/kg/d, and the mean total duration of HC therapy was 23 ± 25 days. Oliguria occurred in 24% (13/54) of treated infants. These infants were exposed to higher and longer duration of the initial HC dose than infants without oliguria. Oliguria was predicted by the initial HC dose (odds ratio [OR] 5.8, 95% confidence interval [CI] 1.3-25.8, p = 0.02) and by the number of days at initial dose (OR 1.7, 95%CI 1.1-2.7, p = 0.03). CONCLUSIONS: Oliguria during HC dosage weaning was associated with higher initial HC exposure.

Examination of pretreatment predictors of attrition in a VLCD and behavior therapy weight-loss program.

Seventeen pretreatment predictors of attrition in a very low-calorie diet (VLCD) and behavior therapy combined weight-loss program (Optifast) were examined. A multiple discriminant function analysis was conducted on historical data in an attempt to distinguish early dropouts (weeks 2-14) from late dropouts (weeks 15-26) from completers. The following seven predictor variables contributed to the significant discriminant function equation: the number of past diets, past emotional difficulties, past physical or emotional difficulties while dieting, expected stress over the next 6 months, the number of close friends, the number of people who annoy the dieter about his or her weight, and the expectation of insurance coverage. In addition, it was found that completers reported a significantly greater number of previous diets than early dropouts.

Field trial of a compound chromosome strain for genetic control of the sheep blowfly Lucilia cuprina.

In 1979-80 a field trial of a compound chromosome (CC) strain of the Australian sheep blowfly Lucilia cuprina was conducted in the isolated Brindabella Valley, N.S.W. New genetic material was introduced into the strain before release by inducing 104 new CC elements by irradiation of recently captured field strains, and combining the resulting strains. Weekly releases, averaging 1.1 million larvae per week, were begun in November 1979 and continued to May 1980. Field-inseminated females were trapped weekly and their genotypes and those of their mates were determined through genetic testing. The proportion of wild X wild matings declined from 16% in December 1979 to 1% in April 1980. During this period the proportion of CC X CC matings rose from 50% to 90%. Larvae sampled from infested sheep had compound chromosomes, indicating that compound chromosomebearing females can successfully oviposit in the field. Trapping of flies resumed at the start of the 1980-81 season, without further releases. Progeny tests revealed the presence of both CC and wild flies. The proportions of CC X CC matings among field-inseminated females were 90% in October, 44% in November, nil in December, and 12% in January. No CC X CC matings were detected in 33 field-inseminated females trapped and tested during April, and 70 tested males reared from myiasis samples in April 1981 proved to be wild type. These results indicate that the CC strain overwintered in the field and strongly suggest that it bred in the field for at least one generation following the spring emergence before being eliminated from the population.