Human Biology

This paper describes the setting up of a nature trail for educational purposes. It discusses the aims, methods of use, and possible evaluation techniques for such a trail. Some probable developments of the ‘trail’ concept at Hartsholme are reviewed. Examples are given of both school-based and leisure-learning activities.     

The Human Intestinal Microbiome: A New Frontier of Human Biology

To analyze the vast number and variety of microorganisms inhabitingthe human intestine, emerging metagenomic technologies are extremelypowerful. The intestinal microbes are taxonomically complexand constitute an ecologically dynamic community (microbiota)that has long been believed to possess a strong impact on humanphysiology. Furthermore, they are heavily involved in the maturationand proliferation of human intestinal cells, helping to maintaintheir homeostasis and can be causative of various diseases,such as inflammatory bowel disease and obesity. A simplifiedanimal model system has provided the mechanistic basis for themolecular interactions that occur at the interface between suchmicrobes and host intestinal epithelia. Through metagenomicanalysis, it is now possible to comprehensively explore thegenetic nature of the intestinal microbiome, the mutually interactingsystem comprising the host cells and the residing microbialcommunity. The human microbiome project was recently launchedas an international collaborative research effort to furtherpromote this newly developing field and to pave the way to anew frontier of human biology, which will provide new strategiesfor the maintenance of human health.     

The Conflict of Pre-Paradigm Schools in Modern Human Origins Research

The debate on the origins of modern humans is one of the oldest and most controversial in the field of palaeoanthropology. In the 1860s the debate was established in the evolutionary context and, as a conflict between two major schools and various sub-schools, it has continued up until the present day. The opposing schools were and still are, at best, in only partial alignment on the major scientific issues. Each of them is founded in its own metaphysics and focuses on an exclusive set of observations that it is capable of explaining. It would appear, therefore, that the history and present state of modern human origins research may be interpreted, in terms of Kuhn's philosophy of science, as an example of a pre-paradigm scientific dispute. This interpretation shows the immaturity of modern human origins research and calls for the re-examination of palaeoanthropology's basic theoretical propositions as well as of this sciencie's controversial relationship with the society.     

Developmental Biology and Human Concerns

There is a large natural loss of human embryos in early gestation.Most conceptual losses occur before pregnancy has been diagnosedin the woman. It is now acknowledged that chromosomal aberrationsare the major etiologic agents responsible for spontaneous abortions.Fully 50 percent of naturally aborted embryos in the first trimesterhave an abnormal karyotype. Most of the chromosomal errors thathave been identified in abortuses are only rarely seen in livebirths.Natural in utero selection is relentless in eliminating 99 percentof the chromosomally abnormal conceptuses through spontaneousabortion. The birth of affected offspring that escape nature'sscreening mechanism can be averted by the option of prenataldiagnosis. The thrust of prenatal diagnosis is to prevent thetragic impact of debilitating genetic disorders. But notallat-risk parents wish to avail themselves of prenatal diagnosisbecause they are unwilling to accept the choice of therapeuticabortion. Prevention of a genetic disorder before implantationwould obviate the necessity of an abortion at a later stageof pregnancy. With this perspective, the correction of the basicgenetic flaw by replacing the faulty gene with a functioningallele is an attractive alternative. Notwithstanding the imprecisetechnology that presently serves to caution against immediateapplication, gene therapy is a reasonable and natural extensionof efforts to ameliorate the effects of severe inherited disorders.     

Surnames in the Study of Human Biology

Use of surname analysis in human population biology depends on surnames being inherited like genes. In societies that meet this condition, communities with a few surnames at high frequency are the more inbred ones, and marriages between persons of the same surname can be used to estimate rates of inbreeding. Furthermore, the degree of commonality of the surnames of two communities estimates their biological relationship provided that any two persons of the same surname derived it from a common ancestor and that virilocal and uxorilocal migration is equal. Although the assumptions are only partially met, the surname method yields results which correlate with the amount of marital migration and with geographical and historical features. Rare surnames meet the assumptions better than common ones. Documents, both old and new, yield surnames of large numbers of people which can easily be analyzed to show the cumulative effect of marital migration since the establishment of surnames (in England in the Middle Ages). Surnames thus serve to delineate the breeding structure of some human populations over a longer span of time than is usually possible with pedigrees, over a more definite span of time than in genetic studies, and more easily in broad surveys than alternative methods . [isonymy, surnames, inbreeding, coefficient of relationship, England]     

Targeting Human Transmission Biology for Malaria Elimination

Malaria remains one of the leading causes of death worldwide, despite decades of public health efforts. The recent commitment by many endemic countries to eliminate malaria marks a shift away from programs aimed at controlling disease burden towards one that emphasizes reducing transmission of the most virulent human malaria parasite, Plasmodium falciparum. Gametocytes, the only developmental stage of malaria parasites able to infect mosquitoes, have remained understudied, as they occur in low numbers, do not cause disease, and are difficult to detect in vivo by conventional methods. Here, we review the transmission biology of P. falciparum gametocytes, featuring important recent discoveries of genes affecting parasite commitment to gametocyte formation, microvesicles enabling parasites to communicate with each other, and the anatomical site where immature gametocytes develop. We propose potential parasite targets for future intervention and highlight remaining knowledge gaps.