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Evolutionary Biology of Parasitism
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Microevolutionary studies are largely involved with monitoring changes in the distribution and frequency of genes in populations (Box 7.1) and with investigating the causes of those changes. You will recall that we have already discussed parasite populations both from the standpoint of being reservoirs of parasite diversity (Chapter 2) and from their complex structure (Chapter 6). Changes in the distribution and frequency of genes in populations are the essence of evolutionary change. Often changes in the abundance of variant forms (called alleles) of particular genes are followed over space and time by evolutionary biologists. Of particular interest is the extent to which basic evolutionary processes such as mutation, gene flow, genetic drift and natural selection can combine to influence the degree of genetic variability within and among populations. The more populations become differentiated from one another, the more structure they are said to possess. Understanding the microevolutionary process and how it affects parasite populations is important because it helps us to gauge the evolutionary or adaptive potential of these populations. For example, how readily might a particular parasite population evolve drug resistance or withstand a control program? Population genetics studies can also provide unique insights into patterns of transmission, host range, reproductive strategies and pathogenicity of parasites. As we will see, what happens at the microevolutionary scale has considerable potential to impact macroevolutionary events such as speciation as well.
The Precision Medicine Approach in Oncology
Published in David E. Thurston, Ilona Pysz, Chemistry and Pharmacology of Anticancer Drugs, 2021
Measurements of genetic variability can be used to establish a link between the variations and disease, and to predict a patient’s therapeutic response to a drug along with potential toxicological outcomes. After completion of the Human Genome Project (HGP) between 2000 and 2003, the next important step was the discovery of new nonredundant genetic markers known as Single-Nucleotide Polymorphisms or “SNPs”. This involved DNA isolation followed by nucleic acid amplification and product detection. Originally, this was a laborious process involving Southern Blots and manual di-deoxy sequencing. The first technological revolution was based on the polymerase chain reaction (PCR), and included assays such as PCR Restriction Length Fragment Polymorphism (PCR-RLFP), PCR-ligase Detection, PCR Fluorescent Resonance Energy Transfer (PCR-FRET), and the nonamplified FRET assay (Invader Assay). The next improvement resulted from automated sequencing instruments (i.e., DNA Sequencers), which allowed high-throughput nucleotide sequencing and pyrosequencing. Finally, a revolution in SNP analysis resulted from the development of SNP Arrays and accompanying bioinformatics software that enabled large-scale linkages to be identified along with association and copy number studies in a low-cost, high-throughput fashion. Based on these developments, a large range of commercial instruments is now available that allow simultaneous measurement of thousands of SNPs across numerous samples using standard protocols, reagents, and data analysis systems.
Introduction to energy aspects of nutrition
Published in Geoffrey P. Webb, Nutrition, 2019
It must be borne in mind when using figures such as those in Table 7.1 that these are estimates of average requirements. They are not intended to be used as an accurate statement of the requirements of individuals. Many different factors will affect the energy expenditure and thus the energy requirements of an individual listed as follows. Size – in general, the bigger the body, the greater the energy expenditure. Body composition – lean tissue is metabolically more active and uses more energy than adipose tissue. Activity level. Environmental conditions such as the ambient temperature. Physiological factors like hormone levels. Rate of growth in children. Individual genetic variability.
The surname structure of Trentino (Italy) and its relationship with dialects and genes
Published in Annals of Human Biology, 2021
Alessio Boattini, Eugenio Bortolini, Roland Bauer, Marta Ottone, Rossella Miglio, Paola Gueresi, Davide Pettener
Our first aim was to investigate the surname structure of Trentino using a wide baptismal record dataset, which covers almost all of the Trentino parishes for the period 1897–1923. As expected, our results clearly show that the distribution of surnames in Trentino is related to geography, thus suggesting that isolation-by-distance patterns had a primary role in shaping the surname structure of Trentino. At the same time, surname diversity was higher in parishes located along the most important valleys (Lagarina, Adige, Sugana), which in turn coincide with the principal communication routes (Figure 1). Of course, these findings reflect well-known patterns of distribution of human genetic variability, both at a local and at a global scale (Slatkin 1993; Ramachandran et al. 2005; Novembre et al. 2008; Salmela et al. 2008; Capocasa et al. 2014).
Genetics of endometriosis: a comprehensive review
Published in Gynecological Endocrinology, 2019
Danilo Deiana, Stefano Gessa, Michela Anardu, Angelos Daniilidis, Luigi Nappi, Maurizio N. D’Alterio, Alessandro Pontis, Stefano Angioni
In endometriosis pathogenesis, the contribution of genetics is well supported by many studies (Figure 1). Human genetic variability can cause a large number of mutations; these mutations are able to alter cellular and molecular mechanisms that, on different levels, are able to facilitate the development and maintenance of the illness. Genetics studies cannot provide a simple and univocal answer on the etiology of the endometriosis. Until now, studies on candidate genes have revealed inconsistent and contradictory evidence, providing more new questions than clear answers. Through GWASs, it has been possible to identify loci that can be explored and, due to NGS, rare genetic variants with a possible association to the illness have been found. Rapid technological advancements in genetics can open doors to meaningful developments in the future, in terms of understanding the molecular mechanisms of pathogenesis, the development and maintenance of endometriosis, and determining the search key for a new therapeutic target in this highly debilitating disease [59].
Geographical distribution and molecular characterization for cutaneous leishmaniasis species by sequencing and phylogenetic analyses of kDNA and ITS1 loci markers in south-eastern Iran
Published in Pathogens and Global Health, 2018
Maryam Ramezany, Iraj Sharifi, Zahra Babaei, Pooya Ghasemi Nejad Almani, Amireh Heshmatkhah, Alireza Keyhani, Mohammad Reza Aflatoonian, Mohammad Ali Mohammadi, Fatemeh Sharifi, Mehdi Bamorovat
Overall, the amplification of kDNA gene is a suitable target for discriminating medically relevant CL species [18,20,21,29,39,40]. The kinetoplast contains about 10,000 min convoluted and circular kDNA minicircles. Such abundance makes the kDNA an appropriate and unique target for numerous diagnostic tests [24]. However, since the species can be associated with certain forms of the disease, parasite identification should not be limited to species determination. In these cases, additional typing techniques are recommended [41]. Since the miniexon sequencing process is cumbersome, ITS1 was amplified and sequenced as a popular and effective marker in Leishmania species typing [40,41]. This kind of information could help in determining strain heterogeneity link to geographical origin. Moreover, the technique has the advantage of detecting genetic variability directly from clinical samples without culturing the causative organism [42].