(n.) The quality of being homologous; correspondence; relation; as, the homologyof similar polygons.
(n.) Correspondence or relation in type of structure in contradistinction to similarity of function; as, the relation in structure between the leg and arm of a man; or that between the arm of a man, the fore leg of a horse, the wing of a bird, and the fin of a fish, all these organs being modifications of one type of structure.
(n.) The correspondence or resemblance of substances belonging to the same type or series; a similarity of composition varying by a small, regular difference, and usually attended by a regular variation in physical properties; as, there is an homology between methane, CH4, ethane, C2H6, propane, C3H8, etc., all members of the paraffin series. In an extended sense, the term is applied to the relation between chemical elements of the same group; as, chlorine, bromine, and iodine are said to be in homology with each other. Cf. Heterology.
Example Sentences:
(1) Trifluoroacetylated rabbit serum albumin was 5 times more reactive with these antibodies and thus more antigenic than the homologous acetylated moiety confirming the importance of the trifluoromethyl moiety as an epitope in the immunogen in vivo.
(2) The ORF2 showed homology with the Escherichia coli regulatory gene ompR, and ORF4 showed homology with E. coli and Rhizobium meliloti regulatory genes fnr and fixK, respectively.
(3) Nucleotide sequence analysis of cDNAs for asparagine synthetase (AS) of Pisum sativum has uncovered two distinct AS mRNAs (AS1 and AS2) encoding polypeptides that are highly homologous to the human AS enzyme.
(4) In four main regions the conservation varied from 83-91% while in the remaining regions the homology dropped to between 56-62%.
(5) It has 61% homology with tRNA(Leu)(anticodon m5CAA) and 63% homology with tRNA(Leu)(anticodon UAG), the two other known yeast tRNAs(Leu).
(6) The specified region of the inner E2 core domain was highly homologous to the region of the E2 subunit of pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase.
(7) This novel mechanism of receptor regulation, named transmodulation, should be distinguished from the reduction in total receptor number caused by the homologous ligand (downregulation) and from the change in affinity produced by the binding of agonists or antagonists to the same receptor site.
(8) This unusual insertion could affect the interaction of cat CD4 with class II molecules, or with FIV, a feline homolog of HIV.
(9) On the basis of primary sequence homology with other known Pseudomonas lipases, a number of putative active site residues located in conserved areas were found.
(10) Extensive sequence homologies and other genetic features are shared with the related oncogenic virus, human papillomavirus type 16, especially in the major reading frames.
(11) Since the plasmid-cured strains did not contain DNA sequences homologous to plasmid DNA, the gene for the free-inclusion protein must be encoded in the chromosome.
(12) Examination of the deduced amino acid sequence revealed an apparent homology to cAMP binding sites in several other proteins.
(13) Thus, introduction of arginine in position 5 with a hydrophobic amino acid in position 6 is compatible with high potency in several biological systems and results in compounds with lowered potency to release histamine compared to homologous peptides with tyrosine in position 5 and D-arginine in position 6.
(14) This receptor and a growing family of related cytokine receptors share homologous extracellular features, including a well-conserved WSXWS motif.
(15) Amino acid analysis indicated a significant number of serine amino acids: N-terminal sequence data demonstrated a high level of homology; and trypsin digestion followed by reversed-phase HPLC indicated the possibility of multiple phosphorylation sites.
(16) Homologous insemination in 52 couples during a period of one year yields a conception rate of 38.5%.
(17) The region is distinctive in that the sequence is absent from the homologous domain of the erythroid alpha chain and diverges from the normal internal repeat structure observed throughout other spectrins.
(18) Surrounding intact ipsilateral structures are more important for the recovery of some of the language functions, such as motor output and phonemic assembly, than homologous contralateral structures.
(19) The results show that in both viral DNAs cleavage occurs at the origin and at one additional site which shows striking sequence homology with the origin region.
(20) The most striking homology was to yeast SEC7 in the central domain of the gene (57% identical over 466 bp) and also the protein level (42% identical amino acids; 39% conserved amino acids).
Homoplasy
Definition:
(n.) See Homogeny.
Example Sentences:
(1) Although the distribution of enamel prism packing patterns among primates suggests considerable homoplasy of this character, this feature does have considerable taxonomic interest at certain hierarchical levels in Primates.
(2) Homoplasy is as prevalent at the few variable sites of conserved regions (18E, 18J, 28F) as at the many variable sites of a more rapidly evolving region (28B).
(3) The pattern with considerable overlap, found in the three classes of amniotes, should be considered an independent development from the same primitive character and should, therefore, be defined as an example of parallel homoplasy.
(4) Further data are needed to decide whether the cell groups in Platyrhinoidis are homologous or homoplasious to their counterparts in land vertebrates.
(5) Cladograms consistently recovered accepted higher level relationships (monophyly of Lepidoptera), despite high homoplasy, but were unable to resolve superfamily and family relationships within Lepidoptera, regardless of the outgroup or character subset analyzed.
(6) Cladistic analyses indicate that the variation in presence of anterior ventral glands is due to homoplasy.
(7) Assignment of observed base substitutions occurring in various branches of the tree reveals an excess of would-be homoplasies in a centrally localized 1.8-kb segment containing the s15 gene.
(8) Matrices of delta Tm's, delta modes, and delta T50Hs were generated and corrected for nonreciprocity, homoplasy, and, in the case of delta Tm's, normalized percent hybridization; these matrices were analyzed using the FITCH algorithm in Felsenstein's PHYLIP (version 3.1).
(9) LeQuesne testing can give information about niche homoplasy, and it may also be possible to see if morphological features are functionally associated with ecological parameters, even if the direction of change is unknown.
(10) Further we offer an approach to structural analysis that demonstrates and quantitates the degree of homoplasy in particular positions of a protein.
(11) Of the many possible hypothetical relationships, the most parsimonious tree showed three homoplasies and allowed the genus Gerbillurus to be paraphyletic.
(12) The alternative trees, depicting larger number of homoplasies but with homoplasies restricted to fusion or fission events, were compatible with the morphological data in supporting the monophyly of Gerbillurus.
(13) Homoplasy, in particular, is a difficulty faced by all methods of phylogenetic inference.
(14) The main primary reasons for untrue or inexplicit morphological phylogenies are: not enough characters developed between branching points, uncertain character polarity, poorly differentiated character states, homoplasy caused by parallelism or reversal, and extinction, which may remove species entirely from consideration and can make originally conflicting data sets misleadingly compatible, increasing congruence at the expense of truth.
(15) The demonstration of extensive homoplasy in a malaria gene raises questions about the validity of familial relationships established among parasites with polymorphic markers.
(16) These include 1) the uncritical assumption of parsimony, 2) uncertainties in the identification of homoplasies, 3) difficulties in the appropriate delimitation of samples for analysis, 4) failure to account for normal patterns of variation, 5) methodological problems with the appropriate identification of morphological traits involving issues of biological relevance, intercorrelation, primary versus secondary characters, and the use of continuous variables, 6) issues of polarity identification, and 7) problems in hypothesis testing.
(17) Further, paleobiogeographic data support the DNA tree rather than the morphological tree, and a plausible heterochronic mechanism has been proposed that may account for the homoplasious morphological evolution that must have occurred if the DNA tree is correct.
(18) An analysis of expected and observed homoplasy revealed that the number of sequence changes uniquely shared by human and chimpanzee lineages is too large to be attributed to homoplasy.
(19) Furthermore, a critical analysis of potential sources of homoplasy (i.e., parallel evolution) reaffirms a Homo-Pan monophyletic clade (Miyamoto et al., 1987).
(20) We suggest that homoplasy at particular positions could mark a site of biological pressure on the parasite where interaction of the site with factors in the environment affects the success of the parasite population.