Later on, the functional significance and universality of this motif were confirmed on 19 Drosophila promoters [ 21].
If the complex developmental processes are disturbed, there is little potential for later repair, and the functional consequences can therefore be permanent (Grandjean and Landrigan 2006; Rice and Barone 2000).
Although there is still a debate on how to define and measure frailty, there is a general agreement in the field that frailty of the later life reflects the functional decline of multiple physiological reserves that limits an elder's ability to respond to external stressors [ 3– 6].
With the exception of the study of Jefferies et al. (2006), both the earlier and later characterizations of the functional syndrome have relied on individual case studies of patients selected for their pattern of performance, the standard methodology of cognitive neuropsychology.
Some years later, Herbert summarized the functional aspects of β-END as follows: this peptide "is particularly concerned with regulating reproductive physiology and is part of the mechanism whereby reproduction is controlled by (and thus responsive to) various elements in the external environment, including social and physical stress" [ 38].
Moreover, it followed a 'diminishing returns' pattern characteristic for the development of a function under selection that is, the activity gain per mutation gradually decreased in later stages of the functional transition, where fitness reached a plateau (Stebbins, 1944; MacLean et al., 2010; Chou et al., 2011; Khan et al., 2011; Tokuriki et al., 2012).
Most kinases mentioned in this review were first identified as enzymes, and only later additional functional functions were identified.
More than twenty years later, the Research Group for functional morphological Studies of the Vertebrates in the Department of Biology (Biotechnical Faculty, University of Ljubljana), is one of the leading groups studying the olm under the guidance of Boris Bulog.
However, as described later, the taxonomic and functional assignment of these genes proved to be more difficult than for human gut microbiota genes.
From an early evolutionary approach into the origin and development of religion, to the later functional, structural and symbolic studies, this encyclopaedia has attempted to include most of the major contributions to the study of religions of tribal societies.
