Developmental Data and Phylogenetic Systematics: Evolution of the Vertebrate Limb

Among the primary contributions of phylogenetic systematicsto the synthesis of developmental biology and evolution arephylogenetic hypotheses. Phylogenetic hypotheses are criticalin interpreting the patterns of evolution of developmental genesand processes, as are morphological data. Using a robust phylogeny,the evolutionary history of individual morphological or developmentalfeatures can be traced and ancestral conditions inferred. Multiplecharacters (e.g., morphological and developmental) can be mappedtogether on the phylogeny, and patterns of character associationcan be quantified and tested for correlation. Using the vertebrate forelimb as an example, I show that bymapping accurate morphological data (homologous skeletal elementsof the vertebrate forelimb) onto a phylogeny, an alternativeinterpretation of Hox gene expression emerges. Teleost fishesand tetrapods may share no homologous skeletal elements in theirforelimbs, and thus similarities and differences in Hox patternsduring limb development must be reinterpreted. Specifically,the presence of the phase III Hox pattern in tetrapods may notbe correlated with digits but rather may simply be the normalexpression pattern of a metapterygium in fishes. This exampleillustrates the rigorous hypotheses that can be developed usingmorphological data and phylogenetic methods. "Creating a general reference system and investigating the relationsthat extend from it to all other possible and necessary systemsin biology is the task of systematics." (Hennig, 1966, p.7)     

The Developmental Origins of Osteoporosis

Osteoporosis is one of the most prevalent skeletal disorders and has enormous public health consequences due to the morbidity and mortality of the resulting fractures. This article discusses the developmental origins of osteoporosis and outlines some of the modifiable and non-modifiable risk factors in both intrauterine and postnatal life that contribute to the later onset of osteoporosis. Evidence for the effects of birth size and early growth in both preterm and term born infants are discussed and the role of epigenetics within the programming hypothesis is highlighted. This review provides compelling evidence for the developmental origins of osteoporosis and highlights the importance of osteoporosis prevention at all stages of the life course.     

Origins of Phantom Limb Pain

Phantom limb pain (PLP) is a chronic neuropathic pain occurring in 45–85% of patients who undergo major amputations of the upper and lower extremities. Chronic pain is physically and mentally debilitating, affecting an individual’s potential for self-care and the performance of daily living activities essential for personal and economic independence. In addition, chronic pain may lead to depression and feelings of hopelessness. A National Center for Biotechnology Information study found that in the USA alone, the annual cost of dealing with neuropathic pain is more than $600 billion, with an estimated 20 million people in the USA suffering this condition. PLP manifest predominantly during two time frames post-amputation: during days to a month and again at around 1 year. In most patients, the frequency and intensity of the chronic neuropathic pain diminish over time, but severe pain persists in about 5–10% of patients. The development and maintenance of neuropathic pain is attributed to extremity amputations causing changes in peripheral axon properties and neuronal circuitry in both the peripheral and central nervous systems: peripheral axons, dorsal root ganglia, the spinal cord, and the cortex. However, it is not clear how the changes in neuronal properties in these different locations affect neuropathic pain. Is pain initiated by one set of post-amputation changes while the pain is maintained by another set of changes? If one set of amputation-induced changes, such as those of peripheral axons, are reverted to normal, is the chronic pain reduced or eliminated, while reversing another set of neuronal changes and neuronal circuits to normal do not reduce or eliminate the pain? Or, must all the amputation-induced changes be reverted to normal for pain to be eliminated? While this review examines the mechanisms underlying the induction or maintenance of PLP, it is beyond its scope to examine the mechanisms that may permanently reduce or eliminate neuropathic pain. This paper is the first of two reviews in this journal and deals with the causes of chronic PLP development and maintenance, while the second review examines potential mechanisms that may be responsible for promoting the capacity to coping with PLP by reducing or eliminating it.     

The Evolution of Human Origins

Because humans are the product of our evolutionary past, learning how we evolved is fundamental to all anthropological investigations. We now realize that reconstructing why unique human attributes evolved requires an understanding of our starting point, but this is a relatively recent perspective. One hundred years ago, the question of human origins was identical to that of hominin origins. Accepting Australopithecus into human ancestry, coupled with the modern synthesis of evolution, led anthropologists to consider humans as products of natural selection. They realized that increased intelligence did not initially distinguish our lineage, and that early hominins were apelike in many ways. Australopithecus brought bipedalityr and brain expansion came with Homo . Because the human mind and behavior are products of evolution, we must reconstruct the selective pressures that shaped our lineage in order to understand ourselves today. Paleoanthropology, as with all anthropology, is becoming ever more question oriented, drawing on many areas of inquiry. [Keywords: human origins, human evolution, history, data, theory]     

灵长类卵母细胞体外发育潜能的调控

灵长类卵母细胞细胞质成熟调控研究较为滞后,使得体外成熟的灵长类卵母细胞的胚胎发育潜能十发低下。提高其潜能对治疗人类不育症有重要的应用价值,并可推动灵长类胚胎发育的研究。基于猕猴卵母细胞质成熟调控研究,讨论了无血清成熟培养基中雌激素和孕激素、能量物质、氨基酸对卵母细胞质成熟的影响,以及动物年龄和生殖周期与发育潜能的关系。从分子水平进一步解释这些因素的作用,阐明卵母细胞质成熟的机理将是今后工作的方向。     

The Roles of Phytoestrogens in Primate Ecology and Evolution

Most primates depend heavily on plant foods; thus their chemical composition is key to understanding primate ecology and evolution. One class of plant compounds of strong current interest are phytoestrogens, which have the potential to alter fertility, fecundity, and survival. These plant compounds mimic the activity of vertebrate estrogens, resulting in altered physiology and behavior. Here, we review what is known about phytoestrogens from an ecological and evolutionary perspective. Much of what is known about the effects of phytoestrogens on the endocrine system comes from research on human foods, especially soybeans (Glycine max). Two opposing perspectives have resulted from this research: 1) phytoestrogens provide health benefits, such as cancer prevention, or 2) phytoestrogens act as endocrine disruptors and threaten reproductive health. Studies of wild primates have only recently begun examining the presence of estrogenic plants in the primate diet and the effects of their consumption. Evidence that a number of primate species eat plants containing phytoestrogens and research documenting behavioral and hormonal effects of estrogenic plant consumption for red colobus monkeys (Procolobus rufomitratus) augment captive and laboratory studies to suggest that these compounds promote differential survival and reproduction. Although much debate is currently taking place over the role of phytoestrogens and other endocrine disruptors in human health issues and in threatening biodiversity, we argue that an ecological and evolutionary approach is needed to reach appropriate conclusions.     

The Origins and Evolution of Culture

This article outlines a deductive theory that creates a new way to think about the origins and evolution of culture. It is Darwinian in the sense that it posits that novel concepts and behavior, like novel genes, appear randomly and are subject to selection on the basis of specific criteria that are established by the properties of living things. The theory permits us to hypothesize properties of the genome that generate culture and to infer the conditions under which selection would favor the origins of culture. Theoretical deductions lead to the conclusion that the organisms that create culture actively participate in the creation of descendants who exhibit increasing cultural abilities and who generate increases in productivity and more reliable flows of resources. Culture is not something that has evolved solely and relatively recently in the hominid line of evolution. Fossil evidence suggests that culture may have existed at least 50 million years ago, and may have originated more than 200 million years ago.     

Evolution of Primate Social Systems

We review evolutionary processes and mechanisms that gave rise to the diversity of primate social systems. We define social organization, social structure and mating system as distinct components of a social system. For each component, we summarize levels and patterns of variation among primates and discuss evolutionary determinants of this variation. We conclude that conclusive explanations for a solitary life and pair-living are still lacking. We then focus on interactions among the 3 components in order to identify main targets of selection and potential constraints for social evolution. Social organization and mating system are more closely linked to each other than either one is to social structure. Further, we conclude that it is important to seek a priori measures for the effects of presumed selective factors and that the genetic contribution to social systems is still poorly examined. Finally, we examine the role of primate socio-ecology in current evolutionary biology and conclude that primates are not prominently represented because the main questions asked in behavioral ecology are often irrelevant for primate behavior. For the future, we see a rapprochement of these areas as the role of disease and life-history theory are integrated more fully into primate socio-ecology.