Mitochondrial DNA in the context of Festuca

The Taíno were the Indigenous peoples of the Greater Antilles and surrounding islands. At the time of European contact in the late 15th century, they were the principal inhabitants of most of what is now The Bahamas, Cuba, the Dominican Republic, Haiti, Jamaica, Puerto Rico, and the northern Lesser Antilles. The Lucayan branch of the Taíno were the first New World people encountered by Christopher Columbus, in the Bahama Archipelago on October 12, 1492. The Taíno historically spoke an Arawakan language. Granberry and Vescelius (2004) recognized two varieties of the Taino language: "Classical Taino", spoken in Puerto Rico and most of Hispaniola, and "Ciboney Taino", spoken in the Bahamas, most of Cuba, western Hispaniola, and Jamaica. They lived in agricultural societies ruled by caciques with fixed settlements and a matrilineal system of kinship and inheritance. Taíno religion centered on the worship of zemis. The Taíno are sometimes also referred to as Island Arawaks or Antillean Arawaks. Indigenous people in the Greater Antilles did not refer to themselves originally as Taíno; the term was first explicitly used in this sense by Constantine Samuel Rafinesque in 1836.

Historically, anthropologists and historians believed that the Taíno were no longer extant centuries ago, or that they gradually merged into a common identity with African and Hispanic cultures. Scholarly attitudes to Taíno survival and resurgence began to change around the year 2000. Many people today identify as Taíno and many more have Taíno descent, most notably in Puerto Rico, Cuba, and Dominica. A substantial number of Puerto Ricans, Cubans, and Dominicans have Indigenous mitochondrial DNA, which may suggest Taíno descent through the direct female line, especially in Puerto Rico. While some communities describe an unbroken cultural heritage passed down through the generations, often in secret, others are revivalist communities who seek to incorporate Taíno culture into their lives.

A genome is all the genetic information of an organism or cell. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences (see non-coding DNA), 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.

The study of the genome is called genomics. The genomes of many organisms have been sequenced and various regions have been annotated. The first genome to be sequenced was that of the virus φX174 in 1977; the first genome sequence of a prokaryote (Haemophilus influenzae) was published in 1995; the yeast (Saccharomyces cerevisiae) genome was the first eukaryotic genome to be sequenced in 1996. The Human Genome Project was started in October 1990, and the first draft sequences of the human genome were reported in February 2001.

The Denisovans or Denisova hominins (/dəˈniːsəvə/ də-NEE-sə-və) are an extinct species or subspecies of archaic human that ranged across Asia during the Middle to Late Pleistocene, approximately 200,000–32,000 years ago. Most of what is known about Denisovans comes from DNA evidence. While many recent fossils have been found and tentatively identified as Denisovan, the first Denisovans discovered were known from few physical remains. Consequently, no formal species name has been established. However, an analysis of the mitochondrial DNA and endogenous proteins from the Harbin cranium, which had been given the name Homo longi, showed with great certainty that this species represents a Denisovan.In a study published in September 2025, remains from six additional sites in China including the 1 million year old Yunxian man were proposed to be included in the species Homo longi along with the genetically confirmed Denisovans.

The first identification of a Denisovan individual occurred in 2010, based on mitochondrial DNA (mtDNA) extracted from a juvenile finger bone excavated from the Siberian Denisova Cave in the Altai Mountains in 2008. Nuclear DNA indicates close affinities with Neanderthals. The cave was also periodically inhabited by Neanderthals. Additional specimens from Denisova Cave were subsequently identified, as were specimens from the Baishiya Karst Cave on the Tibetan Plateau, Tam Ngu Hao 2 Cave in the Annamite Mountains of Laos, the Penghu channel between Taiwan and the mainland, and Harbin in Manchuria.

The takin (Budorcas taxicolor); /ˈtɑːkɪn/ is a large species of ungulate of the subfamily Caprinae found in the eastern Himalayas. It includes four subspecies, the Mishmi takin (B. t. taxicolor), the golden takin (B. t. bedfordi), the Tibetan (or Sichuan) takin (B. t. tibetana), and the Bhutan takin (B. t. whitei).

Whilst the takin has in the past been placed together with the muskox in the tribe Ovibovini, more recent mitochondrial research shows a closer relationship to Ovis (sheep). Its physical similarity to the muskox is therefore an example of convergent evolution. The takin is the national animal of Bhutan.

Neanderthal genetics testing became possible in the 1990s with advances in ancient DNA analysis. In 2008, the Neanderthal genome project published the full sequence Neanderthal mitochondrial DNA (mtDNA), and in 2010 the full Neanderthal genome. Genetic data is useful in testing hypotheses about Neanderthal evolution and their divergence from early modern humans, as well as understanding Neanderthal demography, and interbreeding between archaic and modern humans.

Modern humans and Neanderthals had multiple different interbreeding episodes, but Neanderthal-derived genes in the present-day human genome descends from an episode 250,000 years ago probably in Eurasia, and 47,000 to 65,000 years ago in the Near East. While 20% of the Neanderthal genome survives today, most people only carry about a few percentage points of Neanderthal DNA, and most Neanderthal-derived DNA is non-coding. Neanderthals maintained a low genetic diversity and suffered from inbreeding depression; consequently most Neanderthal genes were probably selected out of the gene pool. Barring hybrid incompatibility or negative selection, most Neanderthal DNA may descend from the children of modern human females and Neanderthal males. Neanderthals also interbred with Denisovans in the Siberian Altai Mountains.

Sperm (pl.: sperm or sperms) is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring (excluding, in most cases, mitochondrial DNA). Animals produce motile sperm with a tail known as a flagellum, which are known as spermatozoa, while some red algae and fungi produce non-motile sperm cells, known as spermatia. Flowering plants contain non-motile sperm inside pollen, while some more basal plants like ferns and some gymnosperms have motile sperm.

Sperm cells form during the process known as spermatogenesis, which in amniotes (reptiles and mammals) takes place in the seminiferous tubules of the testicles. This process involves the production of several successive sperm cell precursors, starting with spermatogonia, which differentiate into spermatocytes. The spermatocytes then undergo meiosis, reducing their chromosome number by half, which produces spermatids. The spermatids then mature and, in animals, construct a tail, or flagellum, which gives rise to the mature, motile sperm cell. This whole process occurs constantly and takes around 3 months from start to finish.

The Hemerobiiformia are a suborder of insects in the order Neuroptera that include most of the lacewings, antlions and their allies. The phylogeny of the Neuroptera was explored in 2014 using mitochondrial DNA sequences. The results indicate that the traditional Hemerobiiformia are paraphyletic, meaning that not all the members of the clade are considered to belong to it, in particular since it would include all the Myrmeleontiformia, with which the Hemerobiiformia were traditionally contrasted. The Osmyloidea, usually included in Hemerobiiformia, actually seem to represent a more ancient lineage basal to Hemerobiiformia as well as Myrmeleontiformia. The broken-up group is shown in the cladogram:

Neopterygii (from Ancient Greek νέος (néos), meaning "new", and πτέρυξ (ptérux), meaning "wing, fin") is a subclass of ray-finned fish (Actinopterygii). Neopterygii includes the Holostei and the Teleostei, of which the latter comprise the vast majority of extant fishes, and over half of all living vertebrate species. While living holosteans include only freshwater taxa, teleosts are diverse in both freshwater and marine environments. Many new species of teleosts are scientifically described each year.

The potentially oldest known neopterygian is the putative "semionotiform" Acentrophorus varians from the Middle Permian of Russia; however, one study incorporating morphological data from fossils and molecular data from nuclear and mitochondrial DNA, places this divergence date at least 284 mya (million years ago), during the Artinskian stage of the Early Permian. Another study suggests an even earlier split (360 myr ago, near the Devonian-Carboniferous boundary).

Extrachromosomal DNA (abbreviated ecDNA) is any DNA that is found off the chromosomes, either inside or outside the nucleus of a cell. Most DNA in an individual genome is found in chromosomes contained in the nucleus. Multiple forms of extrachromosomal DNA exist, and, while some of these serve important biological functions, they can also play a role in diseases such as cancer.

In prokaryotes, nonviral extrachromosomal DNA is primarily found in plasmids, whereas, in eukaryotes extrachromosomal DNA is primarily found in organelles. Mitochondrial DNA is a main source of this extrachromosomal DNA in eukaryotes. The fact that this organelle contains its own DNA supports the hypothesis that mitochondria originated as bacterial cells engulfed by ancestral eukaryotic cells. Extrachromosomal DNA is often used in research into replication because it is easy to identify and isolate.

Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. It adheres to Mendelian inheritance, with information coming from two parents, one male and one female—rather than matrilineally (through the mother) as in mitochondrial DNA.

Spacer DNA is a region of non-coding DNA between genes. The terms intergenic spacer (IGS) or non-transcribed spacer (NTS) are used particularly for the spacer DNA between the many tandemly repeated copies of the ribosomal RNA genes.

In bacteria, spacer DNA sequences are only a few nucleotides long. In eukaryotes, they can be extensive and include repetitive DNA, comprising the majority of the DNA of the genome. In ribosomal DNA, there are spacers within and between gene clusters, called internal transcribed spacer (ITS) and external transcribed spacers (ETS), respectively. In animals, the mitochondrial DNA genes generally have very short spacers. In fungi, mitochondrial DNA spacers are common and variable in length, and they may also be mobile.

Whole genome sequencing (WGS), also known as full genome sequencing or just genome sequencing, is the process of determining the entirety of the DNA sequence of an organism's genome at a single time. This entails sequencing all of an organism's chromosomal DNA as well as DNA contained in the mitochondria and, for plants, in the chloroplast.

Whole genome sequencing has largely been used as a research tool, but was being introduced to clinics in 2014. In the future of personalized medicine, whole genome sequence data may be an important tool to guide therapeutic intervention. The tool of gene sequencing at SNP level is also used to pinpoint functional variants from association studies and improve the knowledge available to researchers interested in evolutionary biology, and hence may lay the foundation for predicting disease susceptibility and drug response.

The human genome is a complete set of DNA sequences for each of the 22 autosomes and the two distinct sex chromosomes (X and Y). A small DNA molecule is found within individual mitochondria. These are usually treated separately as the nuclear genome and the mitochondrial genome.

Human genomes include both genes and various other types of functional DNA elements. The latter is a diverse category that includes regulatory DNA scaffolding regions, telomeres, centromeres, and origins of replication. In addition, there are large numbers of transposable elements, inserted viral DNA, non-functional pseudogenes and simple, highly repetitive sequences. Introns make up a large percentage of the human genome.

Hoilungia is a genus that contains one of the simplest animals and belongs to the phylum Placozoa. Described in 2018, it has only one named species, H. hongkongensis, although there are possible other species. The animal superficially resembles another placozoan, Trichoplax adhaerens, but genetically distinct from it as mitochondrial DNA analysis revealed.

Hoilungia was discovered in brackish water from mangrove swamps in Hong Kong. These organisms are generally found in the biofilm surfaces in tropical and subtropical environments. Phylogenetically, they are placed closest to cnidarians. They are diploblastic animals and are believed to have dorso-ventral polarity along top and bottom body layers. Their body is overtly similar to oral-aboral axis of cnidarians.

The quagga (/ˈkwɑːxɑː/ or /ˈkwæɡə/) (Equus quagga quagga) is an extinct subspecies of the plains zebra that was endemic to South Africa until it was hunted to extinction in the late 19th century. It was long thought to be a distinct species, but mtDNA studies have supported it being a subspecies of plains zebra. A more recent study suggested that it was the southernmost cline or ecotype of the species.

The quagga is believed to have been around 257 cm (8 ft 5 in) long and 125–135 cm (4 ft 1 in – 4 ft 5 in) tall at the shoulders. It was distinguished from other zebras by its limited pattern of primarily brown and white stripes, mainly on the front part of the body. The rear was brown and without stripes, and appeared more horse-like. The distribution of stripes varied considerably between individuals. Little is known about the quagga's behaviour, but it may have gathered into herds of 30–50. Quaggas were said to be wild and lively, yet were also considered more docile than the related Burchell's zebra. They were once found in great numbers in the Karoo of Cape Province and the southern part of the Orange Free State in South Africa.

A circular chromosome is a chromosome in bacteria, archaea, mitochondria, and chloroplasts, in the form of a molecule of circular DNA, unlike the linear chromosome of most eukaryotes.

Most prokaryote chromosomes contain a circular DNA molecule. This has the major advantage of having no free ends (telomeres) to the DNA. By contrast, most eukaryotes have linear DNA requiring elaborate mechanisms to maintain the stability of the telomeres and replicate the DNA. However, a circular chromosome has the disadvantage that after replication, the two progeny circular chromosomes can remain interlinked or tangled, and they must be extricated so that each cell inherits one complete copy of the chromosome during cell division.