Ca2+]i signalling in sperm--making the most of what you've got

Thanks to a worrying decrease in male fertility, understanding how sperm 'work' is a matter both of interest and great importance. Sperm of all animals detect various environmental cues. The 'behavioural' and physiological responses of sperm must be specific, appropriate and correctly timed. Strangely, in a cell with few organelles and minimal cytoplasmic volume, internal Ca(2+) concentration, [Ca(2+)](i), regulates almost all these activities. How does such a simple cell achieve this - and is it as simple as it seems?     

The adaptive value of maladaptive behavior,or you've got to be stupid in order to be smart

The genetic contribution to primate behavior may include a predisposition to vary responses to the same stimuli. Such variability produces a mix of “erroneous” responses to stimuli, but such errors may serve to monitor change in contingencies in the environment. Social relationships are to be regarded as a consequence of monitoring and adapting to a changing social environment rather than as direct consequences of genetic fitness strategies. Primate social behavior represents a much greater degree of fine tuning to specific partners and contexts than could be obtained through genetic programming. Specific responses may serve to produce information and should not necessarily be regarded as optimum solutions to a particular problem. It may be the ability to vary responses and modify behavior that is selected for rather than a particular response itself.     

The sex determination gene shows no founder effect in the giant honey bee, Apis dorsata

Background

All honey bee species (Apis spp) share the same sex determination mechanism using the complementary sex determination (csd) gene. Only individuals heterogeneous at the csd allele develop into females, and the homozygous develop into diploid males, which do not survive. The honeybees are therefore under selection pressure to generate new csd alleles. Previous studies have shown that the csd gene is under balancing selection. We hypothesize that due to the long separation from the mainland of Hainan Island, China, that the giant honey bees (Apis dorsata) should show a founder effect for the csd gene, with many different alleles clustered together, and these would be absent on the mainland.

Methodology/Principal Findings

We sampled A. dorsata workers from both Hainan and Guangxi Provinces and then cloned and sequenced region 3 of the csd gene and constructed phylogenetic trees. We failed to find any clustering of the csd alleles according to their geographical origin, i.e. the Hainan and Guangxi samples did not form separate clades. Further analysis by including previously published csd sequences also failed to show any clade-forming in both the Philippines and Malaysia.

Conclusions/Significance

Results from this study and those from previous studies did not support the expectations of a founder effect. We conclude that because of the extremely high mating frequency of A. dorsata queens, a founder effect does not apply in this species.     

E pluribus unum,no more: from one crystal,many conformations

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A mark in the core: silence no more!

The histone modification repertoire has recently been expanded. Dot1p is a new type of methyltransferase that methylates lysine 79 in the histone H3 core only in its nucleosomal context and has a possible role in marking open chromatin regions.     

Oxymoron no more: the expanding world of heterochromatic genes

Heterochromatin has been oversimplified and even misunderstood. In particular, the existence of heterochromatic genes is often overlooked. Diverse types of genes reside within regions classified as constitutive heterochromatin and activating influences of heterochromatin on gene expression in Drosophila are well documented. These properties are usually considered paradoxical because heterochromatin is commonly portrayed as "silent chromatin". In the past, studies of heterochromatic genes were limited to a few Drosophila genes. However, the recent discovery of several hundred heterochromatic genes in Drosophila, plants and mammals through sequencing projects offers new opportunities to examine the variety of ways in which heterochromatin influences gene expression. Comparative genomics is revealing diverse origins of heterochromatic genes and remarkable evolutionary fluidity between heterochromatic and euchromatic domains. These features justify a broader view of heterochromatin, one that accommodates repressive, permissive and activating effects on gene expression, and recognizes chromosomal and evolutionary transitional states between heterochromatin and euchromatin.     

Enrichment and nonhuman primates: "first, do no harm"

Since the 1998 publication of The Psychological Well-Being of Nonhuman Primates by the National Research Council, and the 1991 implementation of the 1985 Animal Welfare Act Amendment, many formal and informal nonhuman primate enrichment programs have been put into practice. Reports of their successes and failures, however, are few. All programs have at least two things in common: (1) They are best when designed and maintained by teams of individuals with species-specific expertise; (2) the members of those teams, the stakeholders, usually include principal investigators, animal care and use committee members, veterinarians, and animal care staff. Discussions in this article address general principles about enrichment, goals of such programs from the perspective of each of the major stakeholders, and recently published sources of related information. These discussions follow the central premise that enrichment should benefit all involved and "First, do no harm."