Landscape genomics is one of many strategies used to identify relationships between environmental factors and the genetic adaptation of organisms in response to these factors. [1] Landscape genomics combines aspects of landscape ecology, population genetics and landscape genetics. The latter addresses how landscape features influence the population structure and gene flow of organisms across time and space. The field of landscape genomics is distinct from landscape genetics in that it is not focused on the neutral genetic processes, but considers, in addition to neutral processes such as drift and gene flow, explicitly adaptive processes, i.e. the role of natural selection. [2]
Population genomics utilizes outlier tests to identify genetic variation, which rely on identifying high genetic variation in populations. [1] However, more subtle forms of genetic variation can be detected in landscape genomics. Additionally, outlier tests do not aim to, nor do they facilitate the identification of selection pressures from the local environment that caused genetic variation. [1] Contrarily, landscape genomics aims to identify changes in the genome directly resulting from local environmental factors.
Landscape genomics is a relatively new field, made possible by recent technological advances in genetic mapping. Genomics is the study of the genome, otherwise known as the collection of all of the genes in one organism. Landscape genetics uses technology capable of monitoring 5-20 genetic markers at a time, [3] whereas technology has advanced so that it is now capable of mapping an entire genome, including additional types of genetic markers. Landscape genomics analyzes adaptive markers, whereas landscape genetics only analyzes neutral markers. [3] The field of genomics began to grow in the 1970s when new technology was discovered by A.M. Maxam and W. Gilbert, [4] and continued to advance with the widely recognized Human Genome Project. It was the application of the technology and strategies used in genomics to landscape genetics that created the field of landscape genomics. [3]
Landscape genomics makes use of several fields of study. Environmental association analysis is used to link adaptive processes and genetic markers to local environmental factors. [1] This is often done by selecting one environmental factor, e.g. water salinity or altitude. Continuous data from this factor is then aligned with genetic polymorphisms data from an organism inhabiting the same time and place, and data analysis can then be conducted to detect potential correlations. [1]
Gene sequencing is also necessary in order to identify the genetic markers that are to be studied in correlation with environmental factors.
Landscape genomics has provided an opportunity to examine potential implications of climate change based on how organisms respond to changing temperatures and climate. In one example, researchers studied several populations of the black alder tree, and through landscape genomics found that it is highly adaptive to temperature and latitude changes. [5] This has meaningful implications, as it can help researchers predict how the black alder will react to climate change in the future. [5] Together with complementary research on the ecological role of the black alder, it is also possible to predict how the environment surrounding black alder populations will change.
A microsatellite is a tract of repetitive DNA in which certain DNA motifs are repeated, typically 5–50 times. Microsatellites occur at thousands of locations within an organism's genome. They have a higher mutation rate than other areas of DNA leading to high genetic diversity. Microsatellites are often referred to as short tandem repeats (STRs) by forensic geneticists and in genetic genealogy, or as simple sequence repeats (SSRs) by plant geneticists. A microsatellite database can be accessed https://data.ccmb.res.in/msdb/
Genomics is an interdisciplinary field of biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes. In contrast to genetics, which refers to the study of individual genes and their roles in inheritance, genomics aims at the collective characterization and quantification of all of an organism's genes, their interrelations and influence on the organism. Genes may direct the production of proteins with the assistance of enzymes and messenger molecules. In turn, proteins make up body structures such as organs and tissues as well as control chemical reactions and carry signals between cells. Genomics also involves the sequencing and analysis of genomes through uses of high throughput DNA sequencing and bioinformatics to assemble and analyze the function and structure of entire genomes. Advances in genomics have triggered a revolution in discovery-based research and systems biology to facilitate understanding of even the most complex biological systems such as the brain.
Molecular evolution is the process of change in the sequence composition of cellular molecules such as DNA, RNA, and proteins across generations. The field of molecular evolution uses principles of evolutionary biology and population genetics to explain patterns in these changes. Major topics in molecular evolution concern the rates and impacts of single nucleotide changes, neutral evolution vs. natural selection, origins of new genes, the genetic nature of complex traits, the genetic basis of speciation, evolution of development, and ways that evolutionary forces influence genomic and phenotypic changes.
Population genetics is a subfield of genetics that deals with genetic differences within and between populations, and is a part of evolutionary biology. Studies in this branch of biology examine such phenomena as adaptation, speciation, and population structure.
In population genetics, gene flow is the transfer of genetic material from one population to another. If the rate of gene flow is high enough, then two populations will have equivalent allele frequencies and therefore can be considered a single effective population. It has been shown that it takes only "one migrant per generation" to prevent populations from diverging due to drift. Populations can diverge due to selection even when they are exchanging alleles, if the selection pressure is strong enough. Gene flow is an important mechanism for transferring genetic diversity among populations. Migrants change the distribution of genetic diversity among populations, by modifying allele frequencies. High rates of gene flow can reduce the genetic differentiation between the two groups, increasing homogeneity. For this reason, gene flow has been thought to constrain speciation and prevent range expansion by combining the gene pools of the groups, thus preventing the development of differences in genetic variation that would have led to differentiation and adaption. In some cases dispersal resulting in gene flow may also result in the addition of novel genetic variants under positive selection to the gene pool of a species or population
Molecular genetics is a sub-field of biology that addresses how differences in the structures or expression of DNA molecules manifests as variation among organisms. Molecular genetics often applies an "investigative approach" to determine the structure and/or function of genes in an organism's genome using genetic screens. The field of study is based on the merging of several sub-fields in biology: classical Mendelian inheritance, cellular biology, molecular biology, biochemistry, and biotechnology. Researchers search for mutations in a gene or induce mutations in a gene to link a gene sequence to a specific phenotype. Molecular genetics is a powerful methodology for linking mutations to genetic conditions that may aid the search for treatments/cures for various genetics diseases.
Genetic variation is the difference in DNA among individuals or the differences between populations. There are multiple sources of genetic variation, including mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, but other mechanisms such as sexual reproduction and genetic drift contribute to it as well.
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.
Gene duplication is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene. Gene duplications can arise as products of several types of errors in DNA replication and repair machinery as well as through fortuitous capture by selfish genetic elements. Common sources of gene duplications include ectopic recombination, retrotransposition event, aneuploidy, polyploidy, and replication slippage.
A quantitative trait locus (QTL) is a locus that correlates with variation of a quantitative trait in the phenotype of a population of organisms. QTLs are mapped by identifying which molecular markers correlate with an observed trait. This is often an early step in identifying and sequencing the actual genes that cause the trait variation.
In population genetics and population ecology, population size is the number of individual organisms in a population. Population size is directly associated with amount of genetic drift, and is the underlying cause of effects like population bottlenecks and the founder effect. Genetic drift is the major source of decrease of genetic diversity within populations which drives fixation and can potentially lead to speciation events.
Molecular ecology is a field of evolutionary biology that is concerned with applying molecular population genetics, molecular phylogenetics, and more recently genomics to traditional ecological questions. It is virtually synonymous with the field of "Ecological Genetics" as pioneered by Theodosius Dobzhansky, E. B. Ford, Godfrey M. Hewitt, and others. These fields are united in their attempt to study genetic-based questions "out in the field" as opposed to the laboratory. Molecular ecology is related to the field of conservation genetics.
Public health genomics is the use of genomics information to benefit public health. This is visualized as more effective preventive care and disease treatments with better specificity, tailored to the genetic makeup of each patient. According to the Centers for Disease Control and Prevention (U.S.), Public Health genomics is an emerging field of study that assesses the impact of genes and their interaction with behavior, diet and the environment on the population's health.
Panmixia means random mating. A panmictic population is one where all individuals are potential partners. This assumes that there are no mating restrictions, neither genetic nor behavioural, upon the population and that therefore all recombination is possible. The Wahlund effect assumes that the overall population is panmictic.
Population genomics is the large-scale comparison of DNA sequences of populations. Population genomics is a neologism that is associated with population genetics. Population genomics studies genome-wide effects to improve our understanding of microevolution so that we may learn the phylogenetic history and demography of a population.
Neurogenetics studies the role of genetics in the development and function of the nervous system. It considers neural characteristics as phenotypes, and is mainly based on the observation that the nervous systems of individuals, even of those belonging to the same species, may not be identical. As the name implies, it draws aspects from both the studies of neuroscience and genetics, focusing in particular how the genetic code an organism carries affects its expressed traits. Mutations in this genetic sequence can have a wide range of effects on the quality of life of the individual. Neurological diseases, behavior and personality are all studied in the context of neurogenetics. The field of neurogenetics emerged in the mid to late 1900s with advances closely following advancements made in available technology. Currently, neurogenetics is the center of much research utilizing cutting edge techniques.
Reverse ecology refers to the use of genomics to study ecology with no a priori assumptions about the organism(s) under consideration. The term was suggested in 2007 by Matthew Rockman during a conference on ecological genomics in Christchurch, New Zealand. Rockman was drawing an analogy to the term reverse genetics in which gene function is studied by comparing the phenotypic effects of different genetic sequences of that gene. Most researchers employing reverse ecology make use of some sort of population genomics methodology. This requires that a genome scan is performed on multiple individuals from at least two populations in order to identify genomic regions or sites that show signs of selection. These genome scans usually utilize single nucleotide polymorphism (SNP) markers, though use of microsatellites can work as well.
The interdisciplinary research field of Computational and Statistical Genetics uses the latest approaches in genomics, quantitative genetics, computational sciences, bioinformatics and statistics to develop and apply computationally efficient and statistically robust methods to sort through increasingly rich and massive genome wide data sets to identify complex genetic patterns, gene functionalities and interactions, disease and phenotype associations involving the genomes of various organisms. This field is also often referred to as computational genomics. This is an important discipline within the umbrella field computational biology.
Landscape genetics is the scientific discipline that combines population genetics and landscape ecology. It broadly encompasses any study that analyses plant or animal population genetic data in conjunction with data on the landscape features and matrix quality where the sampled population lives. This allows for the analysis of microevolutionary processes affecting the species in light of landscape spatial patterns, providing a more realistic view of how populations interact with their environments. Landscape genetics attempts to determine which landscape features are barriers to dispersal and gene flow, how human-induced landscape changes affect the evolution of populations, the source-sink dynamics of a given population, and how diseases or invasive species spread across landscapes.
Invasion genetics is the area of study within biology that examines evolutionary processes in the context of biological invasions. Invasion genetics considers how genetic and demographic factors affect the success of a species introduced outside of its native range, and how the mechanisms of evolution, such as natural selection, mutation, and genetic drift, operate in these populations. Researchers exploring these questions draw upon theory and approaches from a range of biological disciplines, including population genetics, evolutionary ecology, population biology, and phylogeography.