Alternatives to the Grandmother Hypothesis

We conducted a meta-analysis of 17 studies that tested for an association between grandparental survival and grandchild survival in patrilineal populations. Using two different methodologies, we found that the survival of the maternal grandmother and grandfather, but not the paternal grandmother and grandfather, was associated with decreased grandoffspring mortality. These results are consistent with the findings of psychological studies in developed countries (Coall and Hertwig Behavioral and Brain Sciences 33:1-59, 2010). When tested against the predictions of five hypotheses (confidence of paternity; grandmothering, kin proximity, grandparental senescence, and local resource competition), our meta-analysis results are most in line with the local resource competition hypothesis. In patrilineal and predominantly patrilocal societies, the grandparents who are most likely to live with the grandchildren have a less beneficial association than those who do not. We consider the extent to which these results may be influenced by the methodological limitations of the source studies, including the use of retrospective designs and inadequate controls for confounding variables such as wealth.     

Grandmother hypothesis and primate life histories

The adaptive significance of midlife menopause in human females has long engaged the attention of evolutionary anthropologists. In spite of extensive debate, the problem has only recently been examined in the context of primate life histories. Here I extend those investigations by comparing life history traits in 16 primate species to test predictions generated from life history theory. In humans, late ages of maturity and higher than expected birth rates are systematically associated with extended postmenopausal longevity. Links among these adjustments on the primate pattern can explain how selection could slow somatic senescence without favoring extension of the fertile span. This conclusion is consistent with the observation that our fertile spans are similar to those of other pongids. The shape of the argument herein demonstrates the utility of life history theory for solving problems of adaptive evolution in female life history traits, with consequences for broader arguments regarding human evolution.     

Fiat lux!: Phylogeny and Bioinformatics shed light on GABA functions in plants

The non-protein amino acid γ-aminobutyric acid (GABA) accumulates in plants in response to a wide variety of environmental cues. Recent data point toward an involvement of GABA in tricarboxylic acid (TCA) cycle activity and respiration, especially in stressed roots. To gain further insights into potential GABA functions in plants, phylogenetic and bioinformatic approaches were undertaken. Phylogenetic reconstruction of the GABA transaminase (GABA-T) protein family revealed the monophyletic nature of plant GABA-Ts. However, this analysis also pointed to the common origin of several plant aminotransferases families, which were found more similar to plant GABA-Ts than yeast and human GABA-Ts. A computational analysis of AtGABA-T co-expressed genes was performed in roots and in stress conditions. This second approach uncovered a strong connection between GABA metabolism and glyoxylate cycle during stress. Both in silico analyses open new perspectives and hypotheses for GABA metabolic functions in plants.     

Bioinformatics approaches to quadruplex sequence location

Guanine quadruplex structures are potentially useful therapeutic targets. There have been several studies attempting to locate genomic sequences which are capable of forming these structures. Since the number of potential quadruplex forming sequences which have been identified is so high, several different strategies have been applied to try and determine which of these sequences may be physiologically relevant and which sequences are most likely to form quadruplex structures. These are based on the limited structural information that is currently available and comparative analyses of the location of these sequences with respect to different genomic regions. Sequence information alone is not enough to identify regions of nucleic acid which participate in quadruplex structures, however it is the starting point for quadruplex structure discovery when complemented with further experimentation.     

Bioinformatics goes back to the future

The need to turn raw data into knowledge has led the bioinformatics field to focus increasingly on the manipulation of information. By drawing parallels with both cryptography and artificial intelligence, we can develop an understanding of the changes that are occurring in bioinformatics, and how these changes are likely to influence the bioinformatics job market.     

生物信息学

生物信息学是采用计算机技术和信息论方法研究生命科学中各种生物信息的表达;采集,储存,传递,检索,分析和解读的科学,是现代生命科学与信息科学,计算机科学,数学,统计学,物理学,化学等学科相互渗透和高度交叉形成的学科,本文简要介绍了现代生物信息学的主要研究领域。