Genetics in the context of "Drosophila melanogaster"

Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. Through heredity, variations between individuals can accumulate and cause species to evolve by natural selection. The study of heredity in biology is genetics.

Ecology (from Ancient Greek οἶκος (oîkos)  'house' and -λογία (-logía)  'study of') is the natural science of the relationships among living organisms and their environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere levels. Ecology overlaps with the closely related sciences of biogeography, evolutionary biology, genetics, ethology, and natural history.

Ecology is a branch of biology, and is the study of abundance, biomass, and distribution of organisms in the context of the environment. It encompasses life processes, interactions, and adaptations; movement of materials and energy through living communities; successional development of ecosystems; cooperation, competition, and predation within and between species; and patterns of biodiversity and its effect on ecosystem processes.

Evolutionary biology is a subfield of biology that analyzes the four mechanisms of evolution: natural selection, mutation, genetic drift, and gene flow. The purpose of evolutionary biology is to observe the diversity of life on Earth. The idea of natural selection was first researched by Charles Darwin as he studied bird beaks. The discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology. Huxley was able to take what Charles Darwin discovered and elaborate to build on his understandings.

The investigational range of current research has widened to encompass the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution, such as sexual selection, genetic drift, and biogeography. The newer field of evolutionary developmental biology ("evo-devo") investigates how embryogenesis is controlled, thus yielding a wider synthesis that integrates developmental biology with the fields of study covered by the earlier evolutionary synthesis.

Deoxyribonucleic acid (pronunciation; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids. Alongside proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life.

The two DNA strands are known as polynucleotides as they are composed of simpler monomeric units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds (known as the phosphodiester linkage) between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two separate polynucleotide strands are bound together, according to base pairing rules (A with T and C with G), with hydrogen bonds to make double-stranded DNA. The complementary nitrogenous bases are divided into two groups, the single-ringed pyrimidines and the double-ringed purines. In DNA, the pyrimidines are thymine and cytosine; the purines are adenine and guanine.

The Indo-European migrations are hypothesized migrations of peoples who spoke Proto-Indo-European (PIE) and the derived Indo-European languages, which took place from around 4000 to 1000 BCE, potentially explaining how these related languages came to be spoken across a large area of Eurasia, spanning from the Indian subcontinent and Iranian plateau to Atlantic Europe.

While these early languages and their speakers are prehistoric (lacking documentary evidence), a synthesis of linguistics, archaeology, anthropology and genetics has established the existence of Proto-Indo-European and the spread of its daughter dialects through migrations of large populations of its speakers, as well as the recruitment of new speakers through emulation of conquering elites. Comparative linguistics describes the similarities between various languages governed by laws of systematic change, which allow the reconstruction of ancestral speech (see Indo-European studies). Archaeology traces the spread of artifacts, habitations, and burial sites presumed to be created by speakers of Proto-Indo-European in several stages, from their hypothesized Proto-Indo-European homeland to their diaspora throughout Western Europe, Central Asian, and South Asia, with incursions into East Asia. Recent genetic research, including paleogenetics, has increasingly delineated the kinship groups involved in this movement.

Spaniards, or Spanish people, are an ethnic group native to Spain. Genetically and ethnolinguistically, Spaniards belong to the broader Southern and Western European populations, exhibiting a high degree of continuity with other Indo-European-derived ethnic groups in the region. Spain is also home to a diverse array of national and regional identities, shaped by its complex history. These include various languages and dialects, many of which are direct descendants of Latin, the language imposed during Roman rule. Among them, Spanish (also known as Castilian) is the most widely spoken and the only official language across the entire country.

Commonly spoken regional languages include, most notably, the sole surviving indigenous language of Iberia, Basque, as well as other Latin-descended Romance languages like Spanish itself, Catalan and Galician. Many populations outside Spain have ancestors who emigrated from Spain and share elements of a Hispanic culture. The most notable of these comprise Hispanic America in the Western Hemisphere.

Agoraphobia is an anxiety disorder characterized by symptoms of anxiety in situations where the person perceives their environment to be unsafe with no way to escape. These situations can include public transit, shopping centers, crowds and queues, or simply being outside their home on their own. Being in these situations may result in a panic attack. Those affected will go to great lengths to avoid these situations. In severe cases, people may become completely unable to leave their homes.

Agoraphobia is believed to be due to a combination of genetic and environmental factors. The condition often runs in families, and stressful or traumatic events such as the death of a parent or being attacked may be a trigger. In the DSM-5, agoraphobia is classified as a phobia along with specific phobias and social phobia. Other conditions that can produce similar symptoms include separation anxiety, post-traumatic stress disorder, and major depressive disorder. The diagnosis of agoraphobia has been shown to be comorbid with depression, substance abuse, and suicidal ideation.Without treatment, it is uncommon for agoraphobia to resolve. Treatment is typically with a type of counselling called cognitive behavioral therapy (CBT). CBT results in resolution for about half of people. In some instances, those with a diagnosis of agoraphobia have reported taking benzodiazepines and antipsychotics. Agoraphobia affects about 1.7% of adults. Women are affected about twice as often as men. The condition is rare in children, often begins in adolescence or early adulthood, and becomes more common at age 65 or above.

Allopatric speciation (from Ancient Greek ἄλλος (állos) 'other' and πατρίς (patrís) 'fatherland') – also called geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.

Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information between the two populations leading to reproductive isolation. If the two populations come into contact they will be unable to reproduce—effectively speciating. Other isolating factors such as population dispersal leading to emigration can cause speciation (for instance, the dispersal and isolation of a species on an oceanic island) and is considered a special case of allopatric speciation called peripatric speciation.

Medical genetics is the branch of medicine that involves the diagnosis and management of hereditary disorders. Medical genetics differs from human genetics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics.

In contrast, the study of typically non-medical phenotypes such as the genetics of eye color would be considered part of human genetics, but not necessarily relevant to medical genetics (except in situations such as albinism). Genetic medicine is a newer term for medical genetics and incorporates areas such as gene therapy, personalized medicine, and the rapidly emerging new medical specialty, predictive medicine.

Cell biology, cellular biology, or cytology, is the branch of biology that studies the structure, function, and behavior of the cells. All organisms are made of cells. A cell is the basic unit of life that is responsible for the living and functioning of an organism. Cell biology encompasses both prokaryotic and eukaryotic cells, with subtopics including the study of cell metabolism, cell communication, cell cycle, biochemistry, and cell composition.

The study of cells is performed using microscopy techniques, cell culture, and cell fractionation. These are used for research into how cells function, which ultimately gives insight into larger organisms. Knowing the components of cells and how cells work is fundamental to all biological sciences and is essential for research in biomedical fields such as cancer, and other diseases. Research in cell biology is interconnected to other fields such as genetics, molecular genetics, molecular biology, medical microbiology, immunology, and cytochemistry.