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Drosophila Sechellia
''Drosophila sechellia'' is a species of fruit fly, used in lab studies of speciation because it can mate with ''Drosophila simulans''. ''Drosophila sechellia'' is endemic to (some of) the Seychelles, and was one of 12 fruit fly genomes sequenced for a large comparative study. ''Morinda'' fruit ''Drosophila sechellia'' are known to preferentially lay eggs on toxic '' Morinda'' fruits. Research has shown that a mutation in the gene that inhibits egg production is associated with a reduction in L-DOPA; L-DOPA is a precursor of the fertility-regulating hormone dopamine Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 8 .... ''Morinda'' fruits are rich in L-DOPA, owing to their usually insecticidal capacities. ''Drosophila sechellia'' fertility is reliant on the L-DOPA found in ''Mori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can reproduction, produce Fertility, fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology (biology), morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a binomial nomenclature, two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specifi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophilidae
The Drosophilidae are a diverse, cosmopolitan family of flies, which includes species called fruit flies, although they are more accurately referred to as vinegar or pomace flies. Another distantly related family of flies, Tephritidae, are true fruit flies because they are frugivorous, and include apple maggot flies and many pests. The best known species of the Drosophilidae is ''Drosophila melanogaster'', within the genus ''Drosophila'', also called the "fruit fly." ''Drosophila melanogaster'' is used extensively for studies concerning genetics, development, physiology, ecology and behaviour. Many fundamental biological mechanisms were discovered first in ''D. melanogaster.'' The fruit fly is mostly composed of post-mitotic cells, has a very short lifespan, and shows gradual aging. As in other species, temperature influences the life history of the animal. Several genes have been identified that can be manipulated to extend the lifespan of these insects. Additionally, ''Drosoph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speciation
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book ''On the Origin of Species''. He also identified sexual selection as a likely mechanism, but found it problematic. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion. Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosome numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drosophila Simulans
''Drosophila simulans'' is a species of fly closely related to '' D. melanogaster'', belonging to the same ''melanogaster'' species subgroup. Its closest relatives are ''D. mauritiana'' and ''D. sechellia''. Taxonomy This species was discovered by the fly geneticist Alfred Sturtevant in 1919, when he noticed that the flies used in Thomas Hunt Morgan's laboratory at the Columbia University were actually two distinct species: '' D. melanogaster'' and ''D. simulans''. Males differ in the external genitalia, while trained observers can separate females using colour characteristics. ''D. melanogaster'' females crossed to ''D. simulans'' males produce sterile F1 females and no F1 males. The reciprocal cross produces sterile F1 males and no female progeny. ''Drosophila simulans'' was found later to be closely related to two island endemics, ''D. sechellia'' and ''D. mauritiana''. ''D. simulans'' will mate with these sister species to form fertile females and sterile males, a fact t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morinda
''Morinda'' is a genus of flowering plants in the madder family, Rubiaceae. The generic name is derived from the Latin words ''morus'' " mulberry", from the appearance of the fruits, and ''indica'', meaning "of India". Description Distributed in all tropical regions of the world, ''Morinda'' includes 80 species of trees, shrubs or vines. All ''Morinda'' species bear aggregate or multiple fruits that can be fleshy (like ''Morinda citrifolia'') or dry. Most species of this genus originate in the area of Borneo, New Guinea, Northern Australia and New Caledonia. In traditional Japanese, Korean and Chinese medicine, '' Morinda citrifolia'' is considered to be a herb with biological properties, although there is no confirmed evidence of clinical efficacy. Fossil record The first fossil record for genus ''Morinda'' is from fruit of ''Morinda chinensis'' found in coal dated from the Eocene in the Changchang Basin of Hainan Island, South China. Selected species Plants in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
L-DOPA
-DOPA, also known as levodopa and -3,4-dihydroxyphenylalanine, is an amino acid that is made and used as part of the normal biology of some plants and animals, including humans. Humans, as well as a portion of the other animals that utilize -DOPA, make it via biosynthesis from the amino acid -tyrosine. -DOPA is the precursor to the neurotransmitters dopamine, norepinephrine (noradrenaline), and epinephrine (adrenaline), which are collectively known as catecholamines. Furthermore, -DOPA itself mediates neurotrophic factor release by the brain and CNS. -DOPA can be manufactured and in its pure form is sold as a psychoactive drug with the INN levodopa; trade names include Sinemet, Pharmacopa, Atamet, and Stalevo. As a drug, it is used in the clinical treatment of Parkinson's disease and dopamine-responsive dystonia. -DOPA has a counterpart with opposite chirality, -DOPA. As is true for many molecules, the human body produces only one of these isomers (the -DOPA form). T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dopamine
Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. Dopamine constitutes about 80% of the catecholamine content in the brain. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. Neurotransmitters are synthesized in specific regions of the brain, but affect many regions systemically. The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational component of reward-motivated behavior. The anticipation of most types of rewards increases the level of dopamine in the brain, and ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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