Museomics is the study of genomic data obtained from ancient DNA (aDNA) and historic DNA (hDNA) specimens in museum collections. [1] [2] Early research in this area focused on short sequences of DNA from mitochondrial genes, but sequencing of whole genomes has become possible. [1] Next-generation sequencing (NGS) and high-throughput sequencing (HTS) methods can be applied to the analysis of genetic datasets extracted from collections materials. [3] Such techniques have been described as a "third revolution in sequencing technology". [4] Like radiocarbon dating, the techniques of museomics are a transformative technology. Results are revising and sometimes overturning previously accepted theories about a wide variety of topics such as the domestication of the horse. [5] [6]
Museum collections contain unique resources such as natural history specimens, which can be used for genome-scale examinations of species, their evolution, and their responses to environmental change. Ancient DNA provides a unique window into genetic change over time. It enables scientists to directly study evolutionary and ecological processes, comparing ancient and modern populations, identifying distinct populations, and revealing patterns of change such as extinctions and migrations. [7] [8] [9] Research may be used to identify isolated populations and inform conservation priorities. [2]
However, museum specimens can be poorly preserved and are subject to degradation [7] and contamination. [2] [10] Genomic analyses face considerable challenges as a result of the highly degraded DNA typical of museum specimens. DNA from such samples is often subject to post-mortem nucleotide damage such as the hydrolytic deamination of cytosine (C) to uracil (U) residues. PCR amplification of damaged templates can further substitute uracils with thymine (T), completing a C to T substitution path. Such errors tend to occur towards the ends of molecules, accumulate with time, and can be significant in specimens a century-old or later. Robust genomic and statistical techniques are needed to rigorously detect and avoid errors and genotyping uncertainties when carrying out analyses based on museum collections. [7] Optimal methods for working with hDNA and aDNA can differ as a result of differences in their DNA degradation history. [1]
Museomics also involves destructive sampling, irreversibly removing parts of sometimes rare specimens to obtain DNA. [11] This can be contentious for curators and collection staff, [1] involving a variety of ethical issues around the handling and destruction of objects, colonial acquisition and repatriation practices, and present-day social and political implications of research. Museums, universities and journals are increasingly developing ethics statements, best practices and guidelines for such work. [12] [13]
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA. The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences, and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplasts with a chloroplast genome.
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.
Domestication is a multi-generational mutualistic relationship in which an animal species, such as humans or leafcutter ants, takes over control and care of another species, such as sheep or fungi, to obtain from them a steady supply of resources, such as meat, milk, or labor. The process is gradual and geographically diffuse, based on trial and error.
The neutral theory of molecular evolution holds that most evolutionary changes occur at the molecular level, and most of the variation within and between species are due to random genetic drift of mutant alleles that are selectively neutral. The theory applies only for evolution at the molecular level, and is compatible with phenotypic evolution being shaped by natural selection as postulated by Charles Darwin.
Archaeogenetics is the study of ancient DNA using various molecular genetic methods and DNA resources. This form of genetic analysis can be applied to human, animal, and plant specimens. Ancient DNA can be extracted from various fossilized specimens including bones, eggshells, and artificially preserved tissues in human and animal specimens. In plants, ancient DNA can be extracted from seeds and tissue. Archaeogenetics provides us with genetic evidence of ancient population group migrations, domestication events, and plant and animal evolution. The ancient DNA cross referenced with the DNA of relative modern genetic populations allows researchers to run comparison studies that provide a more complete analysis when ancient DNA is compromised.
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.
In molecular biology and genetics, GC-content is the percentage of nitrogenous bases in a DNA or RNA molecule that are either guanine (G) or cytosine (C). This measure indicates the proportion of G and C bases out of an implied four total bases, also including adenine and thymine in DNA and adenine and uracil in RNA.
Paleogenetics is the study of the past through the examination of preserved genetic material from the remains of ancient organisms. Emile Zuckerkandl and Linus Pauling introduced the term in 1963, long before the sequencing of DNA, in reference to the possible reconstruction of the corresponding polypeptide sequences of past organisms. The first sequence of ancient DNA, isolated from a museum specimen of the extinct quagga, was published in 1984 by a team led by Allan Wilson.
Ancient DNA (aDNA) is DNA isolated from ancient sources. Due to degradation processes ancient DNA is more degraded in comparison with contemporary genetic material. Genetic material has been recovered from paleo/archaeological and historical skeletal material, mummified tissues, archival collections of non-frozen medical specimens, preserved plant remains, ice and from permafrost cores, marine and lake sediments and excavation dirt.
Noninvasive genotyping is a modern technique for obtaining DNA for genotyping that is characterized by the indirect sampling of specimen, not requiring harm to, handling of, or even the presence of the organism of interest. Beginning in the early 1990s, with the advent of PCR, researchers have been able to obtain high-quality DNA samples from small quantities of hair, feathers, scales, or excrement. These noninvasive samples are an improvement over older allozyme and DNA sampling techniques that often required larger samples of tissue or the destruction of the studied organism. Noninvasive genotyping is widely utilized in conservation efforts, where capture and sampling may be difficult or disruptive to behavior. Additionally, in medicine, this technique is being applied in humans for the diagnosis of genetic disease and early detection of tumors. In this context, invasivity takes on a separate definition where noninvasive sampling also includes simple blood samples.
Plant evolution is the subset of evolutionary phenomena that concern plants. Evolutionary phenomena are characteristics of populations that are described by averages, medians, distributions, and other statistical methods. This distinguishes plant evolution from plant development, a branch of developmental biology which concerns the changes that individuals go through in their lives. The study of plant evolution attempts to explain how the present diversity of plants arose over geologic time. It includes the study of genetic change and the consequent variation that often results in speciation, one of the most important types of radiation into taxonomic groups called clades. A description of radiation is called a phylogeny and is often represented by type of diagram called a phylogenetic tree.
Restriction site associated DNA (RAD) markers are a type of genetic marker which are useful for association mapping, QTL-mapping, population genetics, ecological genetics and evolutionary genetics. The use of RAD markers for genetic mapping is often called RAD mapping. An important aspect of RAD markers and mapping is the process of isolating RAD tags, which are the DNA sequences that immediately flank each instance of a particular restriction site of a restriction enzyme throughout the genome. Once RAD tags have been isolated, they can be used to identify and genotype DNA sequence polymorphisms mainly in form of single nucleotide polymorphisms (SNPs). Polymorphisms that are identified and genotyped by isolating and analyzing RAD tags are referred to as RAD markers. Although genotyping by sequencing presents an approach similar to the RAD-seq method, they differ in some substantial ways.
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections, an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode to identify an item in its stock against its reference database. These "barcodes" are sometimes used in an effort to identify unknown species or parts of an organism, simply to catalog as many taxa as possible, or to compare with traditional taxonomy in an effort to determine species boundaries.
A natural history museum or museum of natural history is a scientific institution with natural history collections that include current and historical records of animals, plants, fungi, ecosystems, geology, paleontology, climatology, and more.
Whole genome bisulfite sequencing is a next-generation sequencing technology used to determine the DNA methylation status of single cytosines by treating the DNA with sodium bisulfite before high-throughput DNA sequencing. The DNA methylation status at various genes can reveal information regarding gene regulation and transcriptional activities. This technique was developed in 2009 along with reduced representation bisulfite sequencing after bisulfite sequencing became the gold standard for DNA methylation analysis.
It is widely agreed that the evolutionary lineage of the grey wolf can be traced back 2 million years to the Early Pleistocene species Canis etruscus, and its successor the Middle Pleistocene Canis mosbachensis. The grey wolf Canis lupus is a highly adaptable species that is able to exist in a range of environments and which possesses a wide distribution across the Holarctic. Studies of modern grey wolves have identified distinct sub-populations that live in close proximity to each other. This variation in sub-populations is closely linked to differences in habitat – precipitation, temperature, vegetation, and prey specialization – which affect cranio-dental plasticity.
David P. Mindell is an American evolutionary biologist and author. He is currently a senior researcher at the University of California, Berkeley, Museum of Vertebrate Zoology. Mindell's work is focused on the systematics, conservation and molecular evolution of birds, especially birds of prey. He is known for his 2006 book, The Evolving World in which he explained, for the general public, how evolution applies to everyday life.
Paleogenomics is a field of science based on the reconstruction and analysis of genomic information in extinct species. Improved methods for the extraction of ancient DNA (aDNA) from museum artifacts, ice cores, archeological or paleontological sites, and next-generation sequencing technologies have spurred this field. It is now possible to detect genetic drift, ancient population migration and interrelationships, the evolutionary history of extinct plant, animal and Homo species, and identification of phenotypic features across geographic regions. Scientists can also use paleogenomics to compare ancient ancestors against modern-day humans. The rising importance of paleogenomics is evident from the fact that the 2022 Nobel Prize in physiology or medicine was awarded to a Swedish geneticist Svante Pääbo [1955-], who worked on paleogenomics.
Jose V. Lopez is an American-Filipino Molecular Biologist. He has been a faculty member and Professor of Biology at Nova Southeastern University (NSU) in Dania Beach, Florida, since 2007. Lopez has contributed as a co-founder of the Global Invertebrate Genomics Alliance (GIGA), a community of scientists. He has also participated in the "Porifera—Tree of Life," "Earth Microbiome," and Earth BioGenome projects.
Genome skimming is a sequencing approach that uses low-pass, shallow sequencing of a genome, to generate fragments of DNA, known as genome skims. These genome skims contain information about the high-copy fraction of the genome. The high-copy fraction of the genome consists of the ribosomal DNA, plastid genome (plastome), mitochondrial genome (mitogenome), and nuclear repeats such as microsatellites and transposable elements. It employs high-throughput, next generation sequencing technology to generate these skims. Although these skims are merely 'the tip of the genomic iceberg', phylogenomic analysis of them can still provide insights on evolutionary history and biodiversity at a lower cost and larger scale than traditional methods. Due to the small amount of DNA required for genome skimming, its methodology can be applied in other fields other than genomics. Tasks like this include determining the traceability of products in the food industry, enforcing international regulations regarding biodiversity and biological resources, and forensics.