Molecular clock calculations estimate the origin of stem group Malpighiales at around 100 Mya ( million years ago ) and the origin of crown group Malpighiales at about 90 Mya.

Molecular phylogenetics has also been used to estimate the dates when species diverged, but there is controversy about the reliability of the molecular clock on which such estimates depend.

Molecular clock and fossil dating suggest echidnas split from platypuses 19 – 48 million years ago.

* Molecular clock

Molecular clock users have developed workaround solutions using a number of statistical approaches including maximum likelihood techniques and later Bayesian modeling.

* Molecular clock explanation of the molecular equidistance phenomenon

simple: Molecular clock

# REDIRECT Molecular clock

* Molecular clock hypothesis

Molecular clock analyses suggest that the ancestor of the nesomyines colonized Madagascar about 20-25 million years ago.

* The primary technical reference work on this topic is Nanosystems: Molecular Machinery, Manufacturing, and Computation, an in-depth, physics-based analysis of a particular class of potential nanomachines and molecular manufacturing systems, with extensive analyses of their feasibility and performance.

Molecular studies such as DNA-DNA hybridization ( Sibley & Ahlquist, 1990 ) and sequence analyses fail to resolve the relationships of grebes properly due to insufficient resolution in the former and long-branch attraction in the latter.

Molecular genetic analyses strongly suggest that Pacific cod and Greenland cod ( Gadus ogac ) from Greenland – the Arctic ocean are the same species ; G. ogac is then a junior synonym of G. macrocephalus.

Molecular phylogenetic analyses have proven these three are all distinctive and separate species ; other taxa formerly believed to be unique species or subspecies, such as B. betulicola, B. chippewaensis, B. persoonii, B. quercicola and B. venturii, are now known to be part of a B. edulis species complex with a wide morphological, ecological and geographic range, and that the genetic variability in this complex is low.

Molecular analyses of angiosperms have placed Cistaceae within the Malvales, forming a clade with two families of tropical trees, Dipterocarpaceae and Sarcolaenaceae.

Molecular analyses of phytochrome and phytochrome-like genes in higher plants ( ferns, mosses, algae ) and photosynthetic bacteria have shown that phytochromes evolved from prokaryotic photoreceptors that predated the origin of plants.

Molecular analyses indicated that the 18S rDNA sequences of these sacs were indistinguishable from those of PKX, and the PKX organism was scientifically described as Tetracapsuloides bryosalmonae Canning, Curry, Feist, Longshaw & Okamura 1999, which has been assigned to a new class, the Malacosporea within the phylum Myxozoa.

Molecular analyses of the ITS and 5S rDNA sequences indicate that T. hypoglaucum and T. doianum are not distinct from T. wilfordii, while T. regelii should be recognized as a separate species.

* Downloadable PDF-" Molecular analyses of the Chinese herb Leigongteng ( Tripterygium wilfordii Hook. f.

Molecular and morphological analyses of the cuttlefish Sepia apama indicate a complex population structure.

Molecular clocks have been used to suggest an origin in the Pacific in the Paleocene.

Molecular data suggest that there are four clades within the Cornales: Cornus-Alangium, nyssoids-mastixioids, Hydrangeaceae-Loasaceae, and Grubbia-Curtisia, with Hydrostachyaceae in an uncertain position, possibly basal.

Molecular phylogenies suggest that at least some of the genera traditionally included in Apiaceae as subfamily Hydrocotyloideae appear to be more closely related to Araliaceae, and the inclusion of Hydrocotyle and Trachymene in Araliaceae has been recommended ( Chandler & Plunkett 2004 ).

Molecular studies of the pipits suggest that the genus arose in East Asia around seven million years ago ( mya ), during the Miocene, and that the genus had spread to the Americas, Africa and Europe between 5 and 6 mya.

Molecular studies suggest that this order is the sister to Plecoptera or to Ephemeroptera.

Molecular and behavioral data suggest that it has no close relatives among living ducks and should be placed in a distinct genus ; it is possibly closest to such species as the Garganey and the Northern Shoveler.

Molecular studies suggest that the African and Madeiran populations are closely related and distinct from European populations of both subspecies, suggesting that Madeira was colonized from Africa and that the African population has a long history of isolation from European populations.

Molecular estimates, however, suggest the species may have diverged much earlier, around 11. 7 million years ago.

Molecular studies suggest that Acanthocheilonema viteae either lost their symbionts before they became essential or diverged from other filaroids before Wolbachia acquisition ( Schmidt and Roberts, 2009 ).

Molecular dating studies suggest that both the epidemic groups ( A and B ) started to spread among humans between 1905 and 1961 ( with the central estimates varying between 1932 and 1945 ).

Molecular phylogenetic studies suggest that Pereskia is not monophyletic ( i. e. its species are not the complete set of descendants of a common ancestor ), although the three other subfamilies are.

Later, at the MRC Laboratory of Molecular Biology in Cambridge, England, Altman started the work that led to the discovery of RNase P and the enzymatic properties of the RNA subunit of that enzyme.

* Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K., Walter, P., ( 2002 ), Molecular Biology of the Cell, Fourth Edition, ( 428-429 ) Garland Science, 0-8153-4072-9 ( Web Edition, Free access )

* Soltis, P. S., Soltis, D. E., and Doyle, J. J. ( 1992 ) Molecular systematics of plants.

* Soltis, P. S., Soltis, D. E., and Doyle, J. J. ( 1998 ) Molecular Systematics of Plants II: DNA Sequencing.

* Johansson, Ulf S. & Ericson, Per G. P. ( 2003 ): Molecular support for a sister group relationship between Pici and Galbulae ( Piciformes sensu Wetmore 1960 ).

* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

* Johansson, Ulf S. & Ericson, Per G. P. ( 2003 ): Molecular support for a sister group relationship between Pici and Galbulae ( Piciformes sensu Wetmore 1960 ).

* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

* Fuchs, J .; Ohlson, J. I .; Ericson, Per G. P. & Pasquet, E. ( 2006 ): Molecular phylogeny and biogeographic history of the piculets ( Piciformes: Picumninae ).

* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

A .; Capparella, Angelo P .; Vuilleumier, François ( 2005 ): Molecular phylogenetic relationships among the Geositta miners ( Furnariidae ) and biogeographic implications for avian speciation in Fuego-Patagonia.

* Fjeldså, Jon ; Irestedt, Martin & Ericson, Per G. P. ( 2005 ): Molecular data reveal some major adaptational shifts in the early evolution of the most diverse avian family, the Furnariidae.

* Fjeldså, Jon ; Irestedt, Martin & Ericson, Per G. P. ( 2005 ): Molecular data reveal some major adaptational shifts in the early evolution of the most diverse avian family, the Furnariidae.

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* Sraml, M .; Christidis, L .; Easteal, S .; Horn, P. & Collet, C. ( 1996 ): Molecular Relationships Within Australasian Waterfowl ( Anseriformes ).

* McCracken, Kevin G .; Johnson, William P. & Sheldon, Frederick H. ( 2001 ): Molecular population genetics, phylogeography, and conservation biology of the mottled duck ( Anas fulvigula ).

From its modest beginnings in the 1890s as the first state medical school in Texas, the University of Texas Medical Branch at Galveston ( UTMB ) has developed into a large, sophisticated health science complex with numerous schools and institutes, including: a Graduate School of Biomedical Sciences, School of Medicine, School of Nursing, School of Health Professions, Institute for Human Infections and Immunity, Institute for the Medical Humanities, an affiliated Shriners Burns Hospital, the Sealy Center for Molecular Medicine, the Sealy Center for Structural Biology, the Center for Biodefense and Emerging Infectious Diseases, the Center for Addiction Research, the Educational Cancer Center, the Center for Interdisciplinary Research in Women ’ s Health, the Insyitute for Translational Sciences, the Galveston National Laboratory ( GNL ), the Sealy Center for Cancer Cell Biology, the Sealy Center for Environmental Health and Medicine, the World Health Organization Collaborating Center for Tropical Diseases, the Stark Diabetes Center, the Center for Biomedical Engineering, the Center for Environmental Toxicology, the Sealy Center on Aging, the George P. and Cynthia Woods Mitchell Center for Neurodegenerative Diseases, and the Sealy Center for Vaccine Development.

* McCracken, Kevin G .; Johnson, William P. & Sheldon, Frederick H. ( 2001 ): Molecular population genetics, phylogeography, and conservation biology of the mottled duck ( Anas fulvigula ).

* Arnaiz-Villena A, Ruiz-del-Valle V, Gomez-Prieto P, Reguera R, Parga-Lozano C, Serano-Vela JI ( 2009 ) Estrildinae Finches ( Aves, Passeriformes ) from Africa, South Asia and Australia: a Molecular Phylogeographic Study.

* Arnaiz-Villena A, Ruiz-del-Valle V, Gomez-Prieto P, Reguera R, Parga-Lozano C, Serano-Vela JI ( 2009 ) Estrildinae Finches ( Aves, Passeriformes ) from Africa, South Asia and Australia: a Molecular Phylogeographic Study.

Molecular orbital scheme, illustrating the linear combination of P – R σ * and P 3d orbitals to form PR3 π acceptor orbitals