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Evolutionary Computation
Published in Anand Nayyar, Dac-Nhuong Le, Nhu Gia Nguyen, Advances in Swarm Intelligence for Optimizing Problems in Computer Science, 2018
Anand Nayyar, Surbhi Garg, Deepak Gupta, Ashish Khanna
Molecular genetics provides a microscopic view of a natural evolution. It crosses the general visible phenotypic features, going deeper in the process. The key observation in genetics is the individual being a dual entity. The external feature is phenotypic properties, which are constructed at the level, i.e., internal construction. Genes here may be considered as the functional units of inheritance, encoding the phenotypic characters, i.e., the external factors visible, e.g., fur colour, trail length, etc. Genes may hold many properties from the possible alleles. An allele is one of the possible values a gene can have. Hence, an allele can be said to have a value that a variable can have mathematically. In a natural system, a single gene may affect many phenotypic traits, which is called pleiotropy. In turn, one phenotypic trait can be determined to be the result of a combination of many genes, termed ‘polygene.’ Hence, biologically the phenotypic variations are connected to the genotypic variations, which are actually an outcome of gene mutation, or the recombination of genes by sexual reproduction.
AI and Autoimmunity
Published in Louis J. Catania, AI for Immunology, 2021
A person’s genes are what “predispose” them or provide genetic susceptibility to dysregulate the immune system, which in turn yields chronic inflammation and, in effect, creates the pathological damage to cells, tissues, and organ systems synonymous with autoimmune diseases. The environmental factors mentioned previously (e.g., smoking, pollution) along with the inherited alleles that an individual possesses for a specific gene (the genotype), combine to produce the “phenotype trigger” and the clinical manifestations of the disease state.
Stochastic Models and Markov Chains
Published in William P. Fox, Robert E. Burks, Modeling Change and Uncertainty, 2022
William P. Fox, Robert E. Burks
An allele is one of the two or more alternative forms of a given gene. Alleles differ from each other in the precise DNA sequence in the phenotypes they confer. Consider the genotype frequencies in two different populations with two different alleles (Table 7.4).
Posthumanism: Creation of ‘New Men’ Through Technological Innovation
Published in The New Bioethics, 2021
Only a small percentage of genetic disorders are monogenic, that is, involving or controlled by a single gene. The norm is that disorders are massively polygenic and determined by the interactions of several alleles, as is the case for most human traits (Chabris et al. 2015). Alleles are each of the two or more alternative forms of a gene that come about through mutations in its DNA nucleotide sequence; the size of the mutations can range from one base-pair (single-nucleotide polymorphism, SNP) to several thousands. These alterations in the DNA sequence are called gene variants. Genetic risk of most diseases is conferred by a large number of alleles, including common alleles with small effects that might be detected by a genome-wide association study (GWAS) in which gene variants are found by comparing the genomes of different individuals. For example, schizophrenia is a highly heritable disorder. A multi-stage schizophrenia GWAS study of 36,989 cases and 113,075 controls, identified 128 independent associations distributed in 108 conservatively defined loci (specific positions in a chromosome) that meet genome-wide significance, 83 of which had not been previously reported. The 128 gene variants appeared to account for perhaps 7% of a given person’s actual risk (Schizophrenia Working Group 2014).