''Alloteropsis'' (from the

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

''allotrios'' ("strange") and ''opsis'' ("appearance")) is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Old World The "Old World" is a term for Afro-Eurasia that originated in Europe , after Europeans became aware of the existence of the Americas. It is used to contrast the continents of Africa, Europe, and Asia, which were previously thought of by the ...

plants in the

grass family Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns and ...

.Hitchcock, A. S. 1909. Catalogue of the Grasses of Cuba. Contributions from the United States National Herbarium 12(6): 183–258, vii–xi
''Alloteropsis'' on pages 210-211 The group is widely distributed in

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

parts of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

and

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

, as well as on certain islands in the

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

s. The genus is unusual among plants in that it includes species with both C₃ and C₄ photosynthetic pathways, and ongoing research is investigating these

taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

as a case study in how carbon concentrating mechanisms for photosynthesis evolve in

land plants The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as siste ...

.Ibrahim, D. G., et al. (2009)
A molecular phylogeny of the genus ''Alloteropsis'' (Panicoideae, Poaceae) suggests an evolutionary reversion from C₄ to C₃ photosynthesis.
''Annals of Botany'' 103(1): 127–136. .

Photosynthetic pathway evolution

Most of the species of ''Alloteropsis'' use variants of the C₄ photosynthetic pathway, but ''A. semialata'' ssp. ''eckloniana'' uses the C₃ photosynthetic pathway.

Phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

reconstructions of the evolutionary relationships between these species have led to two

hypotheses A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obser ...

about how photosynthetic pathways have evolved within the group. First, C₄ photosynthesis evolved in three lineages within this group, leading to independently

derived Derive may refer to: * Derive (computer algebra system), a commercial system made by Texas Instruments * ''Dérive'' (magazine), an Austrian science magazine on urbanism *Dérive, a psychogeographical concept See also * *Derivation (disambiguatio ...

realisations of this pathway (the hypothesis of multiple C₄ origins).Christin, P., et al. (2010)
Can phylogenetics identify C4 origins and reversals?
''Trends in Ecology and Evolution'' 25(7): 403–09. Secondly, that there was a single origin of C₄ photosynthesis within the genus, and the C₃ taxon, ''A. s. ecklonia'', was subsequently derived from a C₄

ancestor An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or (recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from whom ...

(the reversion hypothesis). Since C₄ photosynthesis is a complex trait, its evolution followed by a reversion to the ancestral type of C₃ photosynthesis would represent an exception to

Dollo's law Dollo's law of irreversibility (also known as Dollo's law and Dollo's principle), proposed in 1893 by Belgian paleontologist Louis Dollo states that, "an organism never returns exactly to a former state, even if it finds itself placed in condition ...

. The reversion hypothesis is the most

parsimonious Occam's razor, Ockham's razor, or Ocham's razor ( la, novacula Occami), also known as the principle of parsimony or the law of parsimony ( la, lex parsimoniae), is the problem-solving principle that "entities should not be multiplied beyond neces ...

explanation of phylogenetic relationships within ''Alloteropsis''. However, direct evidence for the hypothesis, in the form of C₄

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

s or

pseudogene Pseudogenes are nonfunctional segments of DNA that resemble functional genes. Most arise as superfluous copies of functional genes, either directly by DNA duplication or indirectly by Reverse transcriptase, reverse transcription of an mRNA trans ...

s in the C₃ taxon, is currently lacking.Christin, P., et al. (2012)
Adaptive evolution of C₄ photosynthesis through recurrent lateral gene transfer.
''Current Biology'' 22(5): 445–49. . Instead, two pieces of evidence better support the hypothesis of multiple C₄ origins. First, different variants of C₄ leaf anatomy are found in three different ''Alloteropsis'' lineages. Secondly, key C₄ enzymes ( PEPC and

PEPCK Phosphoenolpyruvate carboxykinase (, PEPCK) is an enzyme in the lyase family used in the metabolic pathway of gluconeogenesis. It converts oxaloacetate into phosphoenolpyruvate and carbon dioxide. It is found in two forms, cytosolic and mitoch ...

) were recruited multiple times to function in C₄ biochemistry across independent lineages. C₄ photosynthetic pathway evolution in ''Alloteropsis'' also represents an example of

adaptive evolution In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

via

horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between Unicellular organism, unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offsprin ...

eukaryote Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacte ...

s. It is the first such example of gene transfer between plant species that are not in direct physical contact (as in a host-parasite relationship). In each case, genes adapted for an important function in C₄ photosynthesis have been transferred from grass lineages that diverged from ''Alloteropsis'' more than 20 million years ago, and independently evolved C₄ photosynthesis. Horizontally inherited genes encode the photosynthesis

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

s PEPC and PEPCK. All other genes expressed in the mature C₄ leaf of ''A. s. semialata'' were vertically inherited from a

common ancestor Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal comm ...

with the C₃ taxon ''A. s. eckloniana''.

Diversity

; Accepted speciesKew World Checklist of Selected Plant Families
/ref> * '' Alloteropsis angusta'' Stapf -

Nigeria Nigeria ( ), , ig, Naìjíríyà, yo, Nàìjíríà, pcm, Naijá , ff, Naajeeriya, kcg, Naijeriya officially the Federal Republic of Nigeria, is a country in West Africa. It is situated between the Sahel to the north and the Gulf o ...

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

Zaire Zaire (, ), officially the Republic of Zaire (french: République du Zaïre, link=no, ), was a Congolese state from 1971 to 1997 in Central Africa that was previously and is now again known as the Democratic Republic of the Congo. Zaire was, ...

Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

Uganda }), is a landlocked country in East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territor ...

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ...

* '' Alloteropsis cimicina'' (L.) Stapf -

sub-Saharan Africa Sub-Saharan Africa is, geographically, the area and regions of the continent of Africa that lies south of the Sahara. These include West Africa, East Africa, Central Africa, and Southern Africa. Geopolitically, in addition to the List of sov ...

Indian Subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

Hainan Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slightly l ...

Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...

, northern

; sparingly naturalized in scattered locations in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

(

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...

).Biota of North America Program 2013 county distribution map, ''Alloteropsis cimicina''
/ref> * '' Alloteropsis paniculata'' (Benth.) Stapf - tropical

Mauritius Mauritius ( ; french: Maurice, link=no ; mfe, label=Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It incl ...

Réunion Réunion (; french: La Réunion, ; previously ''Île Bourbon''; rcf, label= Reunionese Creole, La Rényon) is an island in the Indian Ocean that is an overseas department and region of France. It is located approximately east of the island ...

* '' Alloteropsis papillosa'' Clayton -

Kenya ) , national_anthem = "Ee Mungu Nguvu Yetu"() , image_map = , map_caption = , image_map2 = , capital = Nairobi , coordinates = , largest_city = Nairobi , ...

Tanzania Tanzania (; ), officially the United Republic of Tanzania ( sw, Jamhuri ya Muungano wa Tanzania), is a country in East Africa within the African Great Lakes region. It borders Uganda to the north; Kenya to the northeast; Comoro Islands and ...

Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi ...

Limpopo Limpopo is the northernmost province of South Africa. It is named after the Limpopo River, which forms the province's western and northern borders. The capital and largest city in the province is Polokwane, while the provincial legislature is ...

Mpumalanga Mpumalanga () is a province of South Africa. The name means "East", or literally "The Place Where the Sun Rises" in the Swazi, Xhosa, Ndebele and Zulu languages. Mpumalanga lies in eastern South Africa, bordering Eswatini and Mozambique. It ...

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN and known as "the garden province") is a province of South Africa that was created in 1994 when the Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu) and Natal Province were merged. It is locate ...

* '' Alloteropsis semialata'' (R.Br.) Hitchc. -

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

, northern

New Guinea New Guinea (; Hiri Motu Hiri Motu, also known as Police Motu, Pidgin Motu, or just Hiri, is a language of Papua New Guinea, which is spoken in surrounding areas of Port Moresby (Capital of Papua New Guinea). It is a simplified version of ...

Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capita ...

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

; Formerly included see '' Mayariochloa Scutachne'' * ''Alloteropsis amphistemon - Mayariochloa amphistemon'' * ''Alloteropsis dura - Scutachne dura''

References

External links

Grassbase - The World Online Grass Flora
{{Taxonbar, from=Q2675251 Poaceae genera Panicoideae