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The Mendelian Society in Lund was founded in 1910. The initiative came from two young biologists supported by a wide circle of interested plant breeders and academics. Already from the start the society was dominated by the towering personality Herman Nilsson-Ehle. After two active years, the Society went into temporal hibernation until it resumed its activities in spring 1916, when Nilsson-Ehle was on his way to become Sweden's first professor of genetics. One of the aims of the Society was to launch a scientific journal for local scientists directed at an international audience. After a successful fundraising campaign, Hereditas was started in 1920. One of the original instigators of the Mendelian Society, Robert Larsson, became its first editor, and he remained in this position for more than 30 years. Both he and Nilsson-Ehle were fascinating personalities, deeply rooted in their time's scientific and ideological debates. [ABSTRACT FROM AUTHOR]

Objectives: Growth hormone deficiency (GHD) in adults is associated with decreased extracellular water volume (ECW). In response to GH replacement therapy (GHRT), ECW increases and blood pressure (BP) reduces or remains unchanged. Our primary aim was to study the association between polymorphisms in genes related to renal tubular function with ECW and BP before and 1 year after GHRT. The ECW measures using bioimpedance analysis (BIA) and bioimpedance spectroscopy (BIS) were validated against a reference method, the sodium bromide dilution method (Br−). Design and Methods: Using a candidate gene approach, fifteen single-nucleotide polymorphisms (SNPs) in nine genes with known impact on renal tubular function (AGT, SCNN1A, SCNN1G, SLC12A1, SLC12A3, KCNJ1, STK39, WNK1 and CASR) were genotyped and analyzed for associations with ECW and BP at baseline and with their changes after 1 year of GHRT in 311 adult GHD patients. ECW was measured with the Br−, BIA, and BIS. Results: Both BIA and BIS measurements demonstrated similar ECW results as the reference method. At baseline, after adjustment for sex and BMI, SNP rs2291340 in the SLC12A1 gene was associated with ECW volume in GHD patients (p = 0.039). None of the SNPs influenced the ECW response to GHRT. One SNP in the SLC12A3 gene (rs11643718; p = 0.024) and three SNPs in the SCNN1G gene [rs5723 (p = 0.02), rs5729 (p = 0.016) and rs13331086 (p = 0.035)] were associated with the inter-individual differences in BP levels at baseline. A polymorphism in the calcium-sensing receptor (CASR) gene (rs1965357) was associated with changes in systolic BP after GHRT (p = 0.036). None of these associations remained statistically significant when corrected for multiple testing. Conclusion: The BIA and BIS are as accurate as Br− to measure ECW in GHD adults before and during GHRT. Our study provides the first evidence that individual polymorphisms may have clinically relevant effects on ECW and BP in GHD adults. [ABSTRACT FROM AUTHOR]

Some genetic phenomena originate as mutations that are initially advantageous but decline in fitness until they become distinctly deleterious. Here I give the condition for a mutation--selection balance to form and describe some of the properties of the resulting equilibrium population. A characterization is also given of the fixation probabilities for such mutations. [ABSTRACT FROM AUTHOR]

The International Congresses have played an important role in the history of genetics. The Eighth International Congress, which in 1948 was held in Sweden, celebrated the conclusion of the war against Nazism and many new decisive scientific advances. It also signaled a hardening of the fight against Lysenkoism, which was growing in strength in the Soviet Union. A rare document is available from the Congress-an amateur film made by a young delegate, Nils Nybom. With its help a living description can be given of the scientific and political melees in which the delegates were involved. [ABSTRACT FROM AUTHOR]

The genomes that organisms transmit between generations contain information about different kinds of functions. The genome with the “best” mix and number of genes for these functions is the one that natural selection favours. Here I introduce a new way to model simple organisms with genes for external and internal functions, and use it to study the evolution of genome size. The external functions are exemplified by resource use and the internal functions by mutation control (repair). It is shown that even with a suitable proportion of genes for mutation control, the genomes in the organisms do not forever incorporate genes that increase resource use. Instead they evolve towards an optimal genome of limited size. The optimal proportion of genes for mutation control is shown to have an upper limit given by the ease with which transmission accuracy is improved by adding extra genes for this purpose to the genome. The model illustrates how natural selection on genomes integrates systems for the transmission of genetic information with systems relating to the external adaptation of the organism. It also opens up for other, more detailed theoretical investigations of genome functions. [Copyright &y& Elsevier]

Abstract: One of the goals of environmental risk assessment (ERA) is to understand effects of toxicant exposure on individual organisms and populations. We hypothesized that toxicant exposure can reduce genetic diversity and alter genotype composition, which may ultimately lead to a reduction in the average fitness of the exposed population. To test this hypothesis, we exposed a copepod, Nitocra psammophila, to a toxic reference compound and assayed resulting alterations in genetic structure, i.e. expected heterozygosity and percent polymorphic loci, as well as other population- and fitness-related measures, i.e. population abundance, demographic structure and juvenile growth. The copepods were exposed to 0.11–1.1μg of the pentabromo-substituted diphenyl ether (BDE-47)mg−1 freeze-dried algae for 24 days (i.e. >1 generation). There was no significant decline in total population abundance. However, there were significant alterations in population structure, manifested as diminished proportion of nauplii and increased proportion of copepodites. In addition, individual RNA content in copepodites decreased significantly in exposed individuals, indicating declined growth. Finally, in the exposed populations, heterozygosity was lower and genotype composition was altered compared to the controls. These results therefore confirm the hypothesized reduction in overall genetic variability resulting from toxicant exposure. Multilevel approaches, such as the one used in the present study, may help unravel subtle effects on the population level, thus increasing the predictive capacity of future ERA. [Copyright &y& Elsevier]