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Topic: Homoplasy

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Parallel evolution

Analogous

	Homoplasy Test
		The Homoplasy Test (Maynard Smith and Smith, 1998) aims to measure the importance of recombination between members of a population.
		The test tries to determine if there is a statistically significant excess of homoplasies (shared similarities found in different branches of a phylogenetic tree not inherited directly from an ancestor) derived from the dataset, compared to an estimate of the number of homoplasies expected by mutation in the absence of recombination.
		A 'homoplasy ratio' is calculated which should range from zero, for a clonal population, to one, for a population under free recombination.
	pubmlst.org /software/analysis/start/manual/homoplasy_test.shtml (695 words)

	Homoplasy estimators with a comparison across data types
		Perhaps this is due to the difficulty in defining homoplasy.
		It is impossible to fully separate the notion of homoplasy from its sister homology.
		Specifically, I have shown (a) that there are significant differences in estimated homoplasy between morphological and molecular data, and (b) that there is no significant difference in estimated homoplasy between the third codon position and the combination of the first and second positions.
	repository.upenn.edu /dissertations/AAI3003708 (360 words)

	American Scientist Online - Identical Evolution (Site not responding. Last check: )
		"Homoplasy" is a term invented more than a century ago by E. Ray Lankester to denote correspondences among organisms evoked by similar environments.
		The editors of this volume sought to establish homoplasy as a topic of interest in its own right and to identify the evolutionary processes that produce it.
		As Dan Brooks points out, homoplasy is observed at different levels in the systematic hierarchy and may be explained in terms both of constraints—how the characters themselves are structured biologically—and of recurring selective factors in the ecological environments of the organisms.
	www.americanscientist.org /template/AssetDetail/assetid/28651;jsessionid=aaa9RlORzV09PT (498 words)

	EVOLUTION: Running Out of New States -- Simpson and Sugden 288 (5474): 2099 -- Science
		Homoplasy, the presence of identical states because of evolutionary convergence rather than common ancestry, is the bane of such studies.
		Wagner uses the frequencies of derivations of new morphologic states in cladistic studies of a wide range of animal fossil taxa to demonstrate that limits to the number of states might exist after all.
		As younger taxa introduce homoplasy, the hierarchical structure of the character data deteriorates and maximum congruence among states becomes less likely to reflect homology.
	www.sciencemag.org /cgi/content/summary/288/5474/2099b (375 words)

	Homoplasy - EvoWiki
		Homoplasy occurs when characters are similar, but are not derived from a common ancestor.
		If the characters were similar and were derived from a common ancestor, they would be homologous.
		Homoplasies that are due to convergent evolution are termed analogies.
	wiki.cotch.net /index.php/Homoplasy (120 words)

	Homoplasy
		If a character has evolved more than once, if possessed by two species but not present in the common ancestor, it is called a homoplasy.
		One form of homoplasy is called convergent evolution, it is quite common because different species are often subject to similar selective pressures.
		Homoplasy, when mistaken for homology, can obscure the pattern of evolutionary history.
	www.uic.edu /classes/bios/bios101/Speciation2/sld049.htm (59 words)

	SASB Cladistics Glossary (Site not responding. Last check: )
		Thus, homoplasy is a mistaken hypothesis of homology, which will confound cladistic analyses.
		Homoplasy is either parallelism (= independent gain) or reversal (= loss).
		Similarity of characters without regard to the distinction between synapomorphy, homoplasy and symplesiomorphy.
	www.science.uts.edu.au /sasb/glossary.html (2158 words)

	Mark's Page
		Collard M and O'Higgins P (2001) Ontogeny and homoplasy in the papionin monkey face.
		Collard M and Wood BA (2001) Homoplasy and the early hominid masticatory system: inferences from analyses of living hominoids and papionins.
		Wood, BA and Collard M (2001) Evolving interpretations of Homo.
	bioanth.anth.ubc.ca /MarksPage.htm (560 words)

	Nine porcine microsatellite loci tested for size homoplasy in genetically diverse breeds
		Kind and probability of homoplasy across allelic microsatellite fragments can be investigated using DNA of genetically diverse pig breeds.
		The majority (18) of SNPs occurred in the 5'-flanking regions of the microsatellite repeats, 10 were found in the 3'-flanking regions, and only one SNP occurred within the repeat of the Wild Boar sequence of SW2427.
		We conclude that fragment length analysis of microsatellites is a reliable tool for intraspecific phylogenetic studies, because size homoplasy rates within a species were low.
	www.uni-hohenheim.de /i3v/00068900/307984041.htm (207 words)

	Patterns of Size Homoplasy at 10 Microsatellite Loci in Pumas (Puma concolor) -- Culver et al. 18 (6): 1151 -- ...
		Patterns of Size Homoplasy at 10 Microsatellite Loci in Pumas (Puma concolor) -- Culver et al.
		A model of mutation appropriate to estimate the number of electrophoretically detectable alleles in a finite population.
		Variation of microsatellite size homoplasy across electromorphs, loci, and populations in three invertebrate species.
	mbe.oxfordjournals.org /cgi/content/full/18/6/1151 (2499 words)

	Department of Zoology, University of Oklahoma
		In particular, this involves assessing the relative historical information content of characters that conflict on phylogenetic trees (homoplasy).
		I am developing methods that indicate, when homoplasy is misleading, when homoplasy is not misleading, and how we recognize the difference and make use of this information.
		Quantification of homoplasy for nucleotide transitions and transversions and a reexamination of assumptions in weighted phylogenetic analysis.
	www.ou.edu /cas/zoology/Broughton.htm (435 words)

	Extreme morphological and ecological homoplasy in tropical salamanders -- Parra-Olea and Wake, 10.1073/pnas.131203598 ...
		The transverse processes of the sacral vertebra of Lineatriton are located in an extreme posterior position, and they are directed posteriorly, effectively adding to the relative interlimb distance as compared with the other species.
		The morphology displayed by Oedipina is a common homoplasy in plethodondontid salamanders, seen for example in the distantly related bolitoglossine genus Batrachoseps from California.
		The first is convergence for elongation related to fossorial life shown in comparisons of Lineatriton and Oedipina, while the second is parallelism with respect both to mode of development for elongation and adaptation for fossorial living shown for the paraphyletic taxon Lineatriton.
	www.pnas.org /cgi/content/full/131203598v1 (2643 words)

	Homology: A Concept in Crisis. Origins & Design 18:2. Wells, Jonathan
		For example, the eye of a mouse is structurally similar to the eye of an octopus, yet their supposed common ancestor did not possess such an eye.
		Onedoes not have to look far to see that homology (and therefore homoplasy) is not understood by many biologists.
		In this article we review in broad outline some of the major difficulties with the neo-Darwinian explanation of homology, in particular, the incongruent causal relationship between genes, development, and phenotypic form.
	www.arn.org /docs/odesign/od182/hobi182.htm (3671 words)

	Publications
		Hufford, L. Ontogenetic evolution, clade diversification, and homoplasy.
		In Homoplasy: The Recurrence of Similarity in Evolution, M. Sanderson and L. Hufford (eds.), Academic Press, San Diego.
		Hufford, L. The roles of ontogenetic evolution in the origin of floral homoplasies.
	www.wsu.edu /~hufford/publications.html (563 words)

	Is Homoplasy or Lineage Sorting the Source of Incongruent mtDNA and Nuclear Gene Trees in the Stiff-Tailed Ducks ... (Site not responding. Last check: )
		Homoplasy may be inconsequential for resolving polytomies in cases of very recent speciation, including those where retained ancestral polymorphism is still extant.
		Lineage sorting and homoplasy thus differ in their effects because the potential to resolve a polytomy depends not only on the length of the internode between speciation events but also on the overall time depth of the polytomy (e.g., O'hUigin et al., 2002).
		Given limited homoplasy in the nuclear data, the nuclear topologies can probably be regarded as reasonable accurate gene trees that are in conflict with the results of the mtDNA analysis, particularly with respect, to the relationships of these three species.
	www.redorbit.com /news/display/?id=141487&source=r_science (8821 words)

	Homoplasy \| World of Genetics
		Spines (modified leaves) and thorns (modified stems) are an example of homoplasy among plants; spines and thorns look similar and both provide protection to the plant, but the plants to which they belong are distantly related.
		Bat wings, the front flipper of a whale, and the human arm are homologous because the front limb bones of the common ancestor of these mammals had a similar structure.
		While homoplasy can be an obstacle to determining true phylogeny, it is also an important evolutionary event; convergent evolution, for example, illustrates that unrelated organisms adapted to similar environmental constraints in a similar way.
	www.bookrags.com /research/homoplasy-wog (388 words)

	The impact of microsatellite electromorph size homoplasy on multilocus population structure estimates in a tropical ... (Site not responding. Last check: )
		We investigated the frequency of microsatellite electromorph size homoplasy for 12 loci in the tropical tree Corythophora alta and 11 loci in the anadromous fish Morone saxatilis by sequencing 14-23 homozygotes per locus sampled from multiple populations for a total of 453 sequences.
		Two methods of correction for homoplasy in C. alta generally produced little or no change in single-locus estimates of RST, except for two loci in which some additional differentiation among populations was revealed.
		Twelve-locus estimates of RST (including the seven loci corrected for homoplasy) were slightly greater than estimates from uncorrected data, although the 95% confidence intervals overlapped.
	www.trophort.com /information/data/B01/S05/ADA04THE2571747.html (307 words)

	Evolution - A-Z - Homoplasies (Site not responding. Last check: )
		A homoplasy is a character shared by a set of species but not present in their common ancestor.
		Homoplasies can be compared with homologies, which are characters shared by a set of species and are present in their common ancestor.
		For example, the wings of insects, birds and bats are all needed for flying: they are homoplasious structures in the non-evolutionary, as well as the evolutionary, sense.
	www.blackwellpublishing.com /ridley/a-z/Homoplasies.asp (151 words)

	Homology vs Homogeny (Site not responding. Last check: )
		The term homoplasy was originally coined by the British evolutionary biologist Ray Lankester in 1870.
		Lankester's ideas gained only partial acceptance, as is obvious by the common, though irregular reference to homoplasy in 20th century evolutionary biology, whereas the notion of homogeny has received virtually no positive consideration.
		What I will point out in my talk today is that Lankester's wholesale replacement of the term of homology with the dual terms homogeny and homoplasy were in fact correct, contrary to past commentaries against the use of homogeny in lieu of the continued use of the term homology in evolutionary biology.
	www.nhm.org /research/annelida/homology/sld011.html (145 words)

	* Homoplasy- (Biology): Definition
		Homoplasy is the idea that the same characteristic can arrive by different pathways and not reflect the ancestry, so the alternatives to synapomorphies.
		homoplasy Phenotypic similarity among characteristics of different species or populations (including molecular, morphological, behavioral or other features) that does not accurately represent patterns of common evolutionary descent (= nonhomologous...
		In evolutionary biology, convergent evolution describes the process whereby organisms not closely related independently acquire similar characteristics while evolving in separate and sometimes varying ecosystems.
	en.mimi.hu /biology/homoplasy.html (118 words)

	ISMB 2006: Fortaleza, Brazil, August 6-10 (Site not responding. Last check: )
		Homoplasy between two taxons will make their pairwise dissimilarity appear smaller.
		This means that if there is homoplasy between ingroup taxons i and j, these two will be analysed separately in the context of every other ingroup taxon.
		At the heart of the algorithm is a simple intuitive mechanism, which directly targets the problems of homoplasy and heterogeneous rates of evolution.
	ismb2006.cbi.cnptia.embrapa.br /poster_abstract.php?id=C-42 (1800 words)

	John A. Finarelli's Research Page
		Low preservation in the fossil record could mask actual homoplasy, therefore the lower amount of homoplasy observed in the postcrania could be a function of their incompleteness.
		Thus, with a greater proportion of characters in the data set, the morphologically preferred cladogram could be fundamentally biased in favor of the postcrania and against dental characters, serving to raise the level of homoplasy observed in dental characters.
		The completeness of the dental characters was randomly degraded to that of the postcranial characters, and character weighting was used to equalize the input of both sets of characters in determining the optimal cladogram.
	earth.unh.edu /clyde/jaf/finarelli.html (791 words)

	Homology and Paralogy
		Implicit in an alignment of sequences obtained from different species is that each nucleotide position is homologous and that the observed states are either homologous, homoplasious, or, if all the states differ, neither.
		Thus, homology and homoplasy are defined relative to shared ancestry of the sequences (characters) being compared.
		However, because we do not know for sure whether characters states are homologous or homoplasious, statements of such are hypotheses.
	stripe.colorado.edu /~am/Homo&Para.html (1336 words)

	Convergent evolution - Biocrawler (Site not responding. Last check: )
		Parallel evolution occurs when two independent species evolve together at the same time in the same ecospace and acquire similar characteristics (extinct browsing-horses and extinct paleotheres).
		Structures that are the result of convergent evolution are called analogous structures or homoplasies; they should be contrasted with homologous structures which have a common origin.
		Another example is the aerial rootlets found in English ivy (Hedera helix) and wintercreeper (Euonymus fortunei) (and other vines).
	www.biocrawler.com /encyclopedia/Homoplasy (231 words)

	Zoology 304, Evolution
		Homoplasy is similarity NOT due to homology; resulting from convergence, parallelism or reversal.
		Operationally, a polyphyletic group is defined by convergent traits (homoplasies).
		In practice, the job of reconstructing phylogeny is largely one of distinguishing true synapomorphy from homoplasy.
	www.science.siu.edu /zoology/king/304/ch12.htm (2089 words)

	Teaching Animal Molecular Phylogenetics (Site not responding. Last check: )
		Another problem shared by molecular and morphological characters is homoplasy (nonhomologous characters appearing to be similar in different taxa).
		The same base or amino acid can occur homoplasiously at a position on molecular sequences from two taxa, tending to make the two taxa appear to be more closely related than they really are.
		Because of homoplasy, long branches (molecular sequences that have evolved rapidly or for a long time) appear to be more closely related to each other than do sequences that have evolved slowly or for less time.
	www.mhhe.com /biosci/pae/zoology/animalphylogenetics/section01.mhtml (5259 words)

	Multiple Data Sets, High Homoplasy, and the Phylogeny of Softshell Turtles (Testudines: Trionychidae) - Science - ...
		High homoplasy levels may lead mtDNA studies to spurious conclusions (Naylor and Brown, 1998; Garcia-Machado et al, 1999; Wiens and Hollingsworth, 2000), bringing into question the general utility of mitochondrial data for deep phylogenetic questions (Naylor and Brown, 1998; Matthee et al., 2001).
		Although homoplasy does have the potential to obscure phylogenetic information (Sanderson and Hufford, 1996), several studies have found a positive relationship between level of homoplasy in a data set and the level of resolution in the phylogeny (Sanderson and Donoghue, 1996; Kllersjo et al, 1998,1999), implying that homoplasy may not be all bad.
		Bootstrap support from various analyses of separate and combined mitochondrial data partitions and combined mitochondrial and nuclear partitions for each of the 22 nodes lettered A to V in the topology in Figure 5 are shown in Appendix 1.
	www.redorbit.com /news/display?id=107751 (8408 words)

	Homology and Homoplasy (Site not responding. Last check: )
		And you've got to know the distinction between homology and homoplasy.
		Homoplasy, on the other hand, means similarity due to convergent evolution, but independent origins.
		For instance, take the fin and the caudal fin of tuna and of dolphin; they are similar but have independent histories, and their similarity comes from adaptation to similar environments and functions.
	www1.kcn.ne.jp /~h-uchii/Adaptation/homology.html (83 words)

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