Biological adaptation of man to his environment: heat, cold, altitude, and nutrition.
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Historical and archaeological records indicate that the Maritime and Land Silk Roads played a pivotal role in facilitating Trans-Eurasian migrations and cultural exchanges. However, the extent to which population movements or the spread of ideas shape Chinese Hui populations remains debated. We present the largest genomic resource to date, including 2,280 Hui individuals sequenced or genotyped from 30 diverse regions, to examine the genetic origins, population structure, and biological adaptations of this underrepresented group in global human genome research. We identified a detailed population structure characterized by five distinct genetic lineages of the Hui, influenced by geography and varying gene flow. The admixture history and demographic events suggest that the northwestern and northern Hui lineages emerged from demic diffusion during the Tang and Yuan Dynasties via the Land Silk Road. In contrast, the southern and island Hui lineages reflect cultural diffusion along the Maritime Silk Road, while the mixed southern-northern lineage likely developed through a combination of demic and cultural diffusion. Our findings support a hybrid model for Hui formation, indicating that both demographic processes and sociocultural transmissions contributed to their population history. We identified east-west highly differentiated variants and pre- and post-admixture adaptations in Hui genomes, demonstrating that admixture-driven adaptive or neutral variants impacted susceptibility to cardiovascular diseases and immune- and diet-related traits. These adaptive signatures include post-admixture signals of SLC24A5 and ECHDC1 in the Hui, as well as pre-admixture signals of the HLA region, BCL2A1, and KCNH8 in the East Asian source. Overall, our study suggests that Han-related genetic components helped the Hui population rapidly adapt to new local environments. Additionally, the frequency spectrum of clinically essential variants differed significantly between Hui and Han individuals, emphasizing the importance of including underrepresented populations in genomic research to promote health equity.
Studying material transformations and biotic cycling in artificial ecosystems (AES), we need to know the principles of biological adaptation of active organisms to change in the environment. Microorganisms in AES for water purification are the most active transforming organisms and consumers of the organic substances contained in wastes. Utilization of organic substances is directly connected with the energy fluxes used by AES. According to energy criteria, the energy fluxes used by a biological system tend to reach maximum values under stable conditions. Unutilized substrate concentration decreases as a result of biological adaptations. After a dramatic change in environmental factors, for example, after a sharp increase in the flow rate of organic substances, the biological system is not able to react quickly. The concentration of unutilized substrate increases and the energy flux used by the biological system decreases. The structure of the microbial community also changes, with a decrease in biological diversity. The efficiency of energy use by simple terrestrial ecosystems depends on the energetic intensity and interactions between plants and rhizospheric microorganisms.
Cardiac hypertrophy which occurs during chronic arterial hypertension is one of the numerous examples of biological adaptation to environmental requirements. As such, it is obtained at random by trial and error, and adaptation represents the sum of various modifications in gene expression, including the shift in isomyosin or in iso-Na+,K(+)-ATPase, the decrease in beta 1-adrenergic or muscarinic receptors or in sarcoplasmic reticulum Ca(2+)-ATPase densities, and the unchanged density in calcium channels and current. Some of these changes are beneficial at the cellular level but are finally detrimental for the organism as a whole, such as slowing of maximum shortening velocity (Vmax). The prolonged calcium transient is likely to be a consequence of the various modifications of the membranes phenotype and provides a rational basis for arrhythmogenicity of the hypertrophied heart. There are also detrimental modifications, such as the increased collagen concentration and vascular hypertrophy, which may result from the accompanying changes in plasma content in several hormones or peptides.
Cardiac hypertrophy due to permanent mechanical overloading is only one example among thousands of the general process of biological adaptation. The process is randomly governed and results in at least one thermodynamical benefit: to be adaptational and to induce several changes in gene expression. Some of these changes are detrimental, some can even be useless. The cascade of events which finally leads to a permanent modification of the genetic expression involves an initial signal, likely to be the stretch, a pathway which transducts the signal, and a transient change in genetic expression which transmits competence to the cell to be transformed. The permanent modifications occur at all cellular levels including the sarcomere, sarcolemma, energy metabolism, and extra-cellular matrix, but they are species-specific and differ in the ventricles and the atria.