Assessing suitability for a problem-based learning curriculum: evaluating a new student selection instrument.

Context: A new student selection instrument has been designed to assess candidate suitability for a problem-based learning, small group curriculum.

Objective: To evaluate the performance of the new teamwork selection instrument in terms of its discriminatory power, fairness, validity, reliability and acceptability among candidates.

Sample: A sample of 69 volunteer candidates attending for interview formed 13 teams of 5 or 6 candidates each.

Assessment of progress tests.

Background: Progress testing is a form of longitudinal examination which, in principle, samples at regular intervals from the complete domain of knowledge considered a requirement for medical students on completion of the undergraduate programme. Over the course of the programme students improve their scores on the test, enabling them, as well as staff, to monitor their progress.

Aim: We aimed to review methods which have been used to assess the results of individual tests, and to make recommendations on best practice.

Molecular phylogeny of the speciose vole genus Microtus (Arvicolinae, Rodentia) inferred from mitochondrial DNA sequences.

Voles of the genus Microtus represent one of the most speciose mammalian genera in the Holarctic. We established a molecular phylogeny for Microtus to resolve contentious issues of systematic relationships and evolutionary history in this genus. A total of 81 specimens representing ten Microtus species endemic to Europe as well as eight Eurasian, six Asian and one Holarctic species were sequenced for the entire cytochrome b gene (1140 bp).

New perspectives--approaches to medical education at four new UK medical schools.

With the expansion in UK medical student numbers, four new medical schools have been established. The authors, all senior faculty members at these new schools at the time of writing, discuss how much the schools have in common in their approaches to medical education

The tobacco mouse and its relatives: a "tail" of coat colors, chromosomes, hybridization and speciation.

The article reviews over 30 years' study of the chromosomal variation of the western house mice (Mus musculus domesticus) from the neighboring valleys of Poschiavo and Valtellina on the Swiss-Italian border. This is done in the context of the social and political history of this area, on the grounds that mice, as commensals, are influenced by human history. The chromosomal study of mice in this area was initiated because their unusual black coat color led a 19th century naturalist to describe the "tobacco mice" from Val Poschiavo as a separate species (Mus poschiavinus).

A role for Saccharomyces cerevisiae Chk1p in the response to replication blocks.

Replication blocks and DNA damage incurred during S phase activate the S-phase and intra-S-phase checkpoint responses, respectively, regulated by the Atrp and Chk1p checkpoint kinases in metazoans. In Saccharomyces cerevisiae, these checkpoints are regulated by the Atrp homologue Mec1p and the kinase Rad53p. A conserved role of these checkpoints is to block mitotic progression until DNA replication and repair are completed.

Stopped for repairs: a new role for nutrient sensing pathways?

In order to prevent division of damaged chromosomes, cells activate a checkpoint to inhibit mitotic progression in order to repair the damaged DNA. Upon detection of DNA damage two downstream checkpoint kinases, Chk1 and Rad53, are activated by the sensor kinase, Mec1, to block the metaphase to anaphase transition and mitotic exit, respectively. Recent data from studies with budding yeast suggested that the DNA damage checkpoint also enlists the cAMP dependent protein kinase (PKA) pathway, which is an integral part of the nutrient sensing mechanism in budding yeast, to inhibit mitosis in response to DNA damage.

Linkage-dependent gene flow in a house mouse chromosomal hybrid zone.

In the alpine valley of Valtellina there are two Robertsonian chromosomal races of house mouse, the Poschiavo (POS: 2n = 24-26) characterized by metacentric 8.12 and acrocentrics 2 and 10 and the Upper Valtellina (UV: 2n = 22-24) characterized by metacentrics 2.8 and 10.

Teaching anatomy without cadavers.

Background: Anatomy learning is generally seen as essential to medicine, and exposure to cadavers is generally seen as essential to anatomy learning around the world. Few voices dissenting from these propositions can be identified.

Aims: This paper aims to consider arguments relating to the use of cadavers in anatomy teaching, and to describe the rationale behind the decision of a new UK medical school not to use cadaveric material.

The DNA damage checkpoint and PKA pathways converge on APC substrates and Cdc20 to regulate mitotic progression.

The conserved checkpoint kinases Chk1 and Rad53-Dun1 block the metaphase to anaphase transition by the phosphorylation and stabilization of securin, and block the mitotic exit network regulated by the Bfa1-Bub2 complex. However, both chk1 and rad53 mutants are able to exit from mitosis and initiate a new cell cycle, suggesting that both pathways have supporting functions in restraining anaphase and in blocking the inactivation of mitotic cyclin-Cdk1 complexes. Here we find that the cyclic-AMP-dependent protein kinase (PKA) pathway supports Chk1 in the regulation of mitosis by targeting the mitotic inducer Cdc20.

Spermatozoal traits and sperm competition in Atlantic salmon: relative sperm velocity is the primary determinant of fertilization success.

Sperm competition occurs when sperm from more than one male compete for fertilizations. This form of post-copulatory sexual selection is recognized as a significant and widespread force in the evolution of male reproductive biology and as a key determinant of differential male reproductive success. Despite its importance, however, detailed mechanisms of sperm competition at the gamete level remain poorly understood.

A highly divergent mitochondrial DNA lineage of Microtus agrestis in southern Europe.

The Mediterranean peninsulas constitute important areas for endemism and intraspecific variation, and are likely places for cryptic biodiversity. We assessed the phylogeographic pattern of field voles (Microtus agrestis) in southern and central Europe by sequence analysis of a 385-bp fragment of the mitochondrial cytochrome b gene in 74 specimens from 44 localities. The majority of samples consisted of skulls collected from owl pellets.

How did pygmy shrews colonize Ireland? Clues from a phylogenetic analysis of mitochondrial cytochrome b sequences.

There is a long-standing debate as to how Ireland attained its present fauna; we help to inform this debate with a molecular study of one species. A 1110 base pair fragment of the mitochondrial cytochrome b gene was sequenced in 74 specimens of the pygmy shrew, Sorex minutus, collected from throughout its western Palaearctic range. Phylogenetic analysis of these sequences revealed several well-supported lineages.

A novel mutation in ferroportin1 is associated with haemochromatosis in a Solomon Islands patient.

Background: A severe form of iron overload with the clinicopathological features of haemochromatosis inherited in an autosomal dominant manner has been described in the Solomon Islands. The genetic basis of the disorder has not been identified. The disorder has similarities to type 4 haemochromatosis, which is caused by mutations in ferroportin1.

Phylogeography of the common vole (Microtus arvalis) with particular emphasis on the colonization of the Orkney archipelago.

To investigate the human introduction of the common vole Microtus arvalis onto the Orkney islands, the complete cytochrome b gene was sequenced in 41 specimens from both Orkney (four localities) and elsewhere in their range (26 localities). Orkney voles belonged to the same phylogenetic lineage, 'Western', as individuals from France and Spain indicating southwestern Europe as the most likely source area for the islands. This result is of interest with respect to the movement and trading links of the Neolithic people who likely transported the voles.

Selection for medical school: just pick the right students and the rest is easy!

Background/aims: The new Peninsula Medical School (PMS) admitted its first undergraduate cohort in September 2002. Development of a new school has given rise to opportunities for critical appraisal of best practice in selecting students for medical school and development of new ways forward.

Methods: The authors developed a selection strategy and principles grounded in the objectives of the PMS programme and drawing extensively on best practice in assessment.

Studies of mitochondrial DNA, allozyme and morphometric variation in a house mouse hybrid zone.

An unusual chromosomal hybrid zone of the house mouse, Mus musculus domesticus, exists in Upper Valtellina, Northern Italy, consisting of four Robertsonian (Rb) races and the standard (all-acrocentric, or 2n = 40) race, all hybridizing freely within 10 km2. The hybrid zone in Valtellina provides an excellent opportunity to study the role of Rb fusions in reproductive isolation and speciation. This hybrid zone has already been well studied for the distribution of Rb fusions and the fertility of hybrids, but in order to understand the dynamics of the zone, a basic understanding of the origin and genetic similarity of the chromosomal races is necessary.

Phylogeography of field voles (Microtus agrestis) in Eurasia inferred from mitochondrial DNA sequences.

In a distribution-wide phylogeographic survey of the field vole (Microtus agrestis), 75 specimens from 56 localities across Eurasia were examined for DNA sequence variation along the whole 1140 base pair (bp) mitochondrial (mt) cytochrome b gene. The species is subdivided into three main mtDNA phylogeographic groups - western, eastern and southern - with largely allopatric distributions. The western phylogeographical group is found in west and central Europe and spread most probably from a glacial refugium in the Carpathians.

The effect of multiple simple Robertsonian heterozygosity on chromosome pairing and fertility of wild-stock house mice (Mus musculus domesticus).

The influence of Robertsonian (Rb) heterozygosity on fertility has been the subject of much study in the house mouse. However, these studies have been largely directed at single simple heterozygotes (heterozygous for a single Rb metacentric) or complex heterozygotes (heterozygous for several to many metacentrics which share common chromosome arms). In this paper we describe studies on male multiple simple heterozygotes, specifically the F(1) products of crosses between wild-stock mice homozygous for four or seven metacentrics and wild-stock mice with a standard all-acrocentric karyotype; these F(1) products were characterized by four and seven trivalents at meiosis I, respectively.

Sex chromosome aneuploidy in wild small mammals.

We describe four examples of the XO condition in wild mammals. One XO house mouse (Mus musculus domesticus) was caught in nature and subsequently gave birth to three litters in captivity, confirming for wild mice the fertility observed for XO laboratory mice. Two other XO house mice were produced from laboratory crosses of wild-caught mice.