Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “rate of evolution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources

Phylogenetic analyses of fat body endosymbionts reveal differences in invasion times of blaberid wood-feeding cockroaches (Blaberidae: Panesthiinae) into the Japanese archipelago.

Cockroaches have endosymbiotic bacteria in their fat bodies. Recent molecular phylogenetic analyses on both hosts and endosymbionts have revealed that co-evolution has occurred throughout the history of cockroaches and termites. Co-cladogenesis was also shown among closely related taxa (woodroach genus Cryptocercus; Cryptocercidae), and thus endosymbiont data are likely to be useful for biogeographical analyses. To test the possibility of co-cladogenesis among inter-and intraspecific taxa, as well as the utility of endosymbiont data for inferring biogeographical scenarios, we analyzed rRNA genes of endosymbionts of Japanese and Taiwanese Panesthiinae (Salganea and Panesthia; Blaberidae), on which phylogenetic analyses previously had been performed based on the mitochondrial genes. Statistical analyses on the topologies inferred from both endosymbiont and host mitochondria genes showed that co-cladogenesis has occurred. The endosymbiont sequences examined appear to have evolved in a clock-like manner, and their rate of evolution based on the host fossil data showed a major difference in the time of invasion of the two Japanese genera, that is congruent with the recent analyses of their mitochondrial genes.

Animals↗

Reconstructing the diversification of alpha-esterases: comparing the gene clusters of Drosophila buzzatii and D. melanogaster.

A cluster composed of 10 active alpha-esterase genes and a pseudogene is distributed over 60 kb in the Drosophila melanogaster genome. This paper describes the corresponding cluster in Drosophila buzzatii, whose lineage diverged from that of D. melanogaster when the subgenera Drosophila and Sophophora diverged about 50 Mya. With three exceptions we find that the composition of the cluster is conserved in the two lineages. The location of alpha E1 in D. melanogaster differs from that of its nearest relative in D. buzzatii, and alpha E4 has duplicated independently in the two lineages. The nature of these differences indicates that a mechanism exists whereby copies of genes can be placed in opposite orientation and nonadjacent positions within a gene cluster, although this does not seem to be a feature of earlier events in the cluster's evolution. The rates of amino acid change are not significantly different between orthologs, but the rates differ sevenfold among paralogs, indicating that very different selective forces are acting on the genes of the cluster. Mapping of sequence differences onto a model of the tertiary structure of the enzymes indicates that motifs contributing to substrate binding and catalysis have changed radically in the alphaE4s and suggest that this subgroup of alpha-esterases may be evolving into a substantially different functional niche.

Animals↗

Lack of evolutionary stasis during alternating replication of an arbovirus in insect and mammalian cells.

The evolution of vesicular stomatitis virus (VSV) in a constant environment, consisting of either mammalian or insect cells, has been compared to the evolution of the same viral population in changing environments consisting in alternating passages in mammalian and insect cells. Fitness increases were observed in all cases. An initial fitness loss of VSV passaged in insect cells was noted when fitness was measured in BHK-21 cells, but this effect could be attributed to a difference of temperature during VSV replication at 37 degrees C in BHK-21 cells. Sequencing of nucleotides 1-4717 at the 3' end of the VSV genome (N, P, M and G genes) showed that at passage 80 the number of mutations accumulated during alternated passages (seven mutations) is similar or larger than that observed in populations evolving in a constant environment (two to four mutations). Our results indicate that insect and mammalian cells can constitute similar environments for viral replication. Thus, the slow rates of evolution observed in natural populations of arboviruses are not necessarily due to the need for the virus to compromise between adaptation to both arthropod and vertebrate cell types.

Adaptation, Physiological↗

Comparative genomics and evolution of proteins associated with RNA polymerase II C-terminal domain.

The C-terminal domain (CTD) of the largest subunit of RNA polymerase II provides an anchoring point for a wide variety of proteins involved in mRNA synthesis and processing. Most of what is known about CTD-protein interactions comes from animal and yeast models. The consensus sequence and repetitive structure of the CTD is conserved strongly across a wide range of organisms, implying that the same is true of many of its known functions. In some eukaryotic groups, however, the CTD has been allowed to degenerate, suggesting a comparable lack of essential protein interactions. To date, there has been no comprehensive examination of CTD-related proteins across the eukaryotic domain to determine which of its identified functions are correlated with strong stabilizing selection on CTD structure. Here we report a comparative investigation of genes encoding 50 CTD-associated proteins, identifying putative homologs from 12 completed or nearly completed eukaryotic genomes. The presence of a canonical CTD generally is correlated with the apparent presence and conservation of its known protein partners; however, no clear set of interactions emerges that is invariably linked to conservation of the CTD. General rates of evolution, phylogenetic patterns, and the conservation of modeled tertiary structure of capping enzyme guanylyltransferase (Cgt1) indicate a pattern of coevolution of components of a transcription factory organized around the CTD, presumably driven by common functional constraints. These constraints complicate efforts to determine orthologous gene relationships and can mislead phylogenetic and informatic algorithms.

Amino Acid Sequence↗

Origin and evolution of eukaryotic chaperonins: phylogenetic evidence for ancient duplications in CCT genes.

Chaperonins are oligomeric protein-folding complexes which are divided into two distantly related structural classes. Group I chaperonins (called GroEL/cpn60/hsp60) are found in bacteria and eukaryotic organelles, while group II chaperonins are present in archaea and the cytoplasm of eukaryotes (called CCT/TriC). While archaea possess one to three chaperonin subunit-encoding genes, eight distinct CCT gene families (paralogs) have been characterized in eukaryotes. We are interested in determining when during eukaryotic evolution the multiple gene duplications producing the CCT subunits occurred. We describe the sequence and phylogenetic analysis of five CCT genes from TRICHOMONAS: vaginalis and seven from GIARDIA: lamblia, representatives of amitochondriate protist lineages thought to have diverged early from other eukaryotes. Our data show that the gene duplications producing the eight CCT paralogs took place prior to the organismal divergence of TRICHOMONAS: and GIARDIA: from other eukaryotes. Thus, these divergent protists likely possess completely hetero-oligomeric CCT complexes like those in yeast and mammalian cells. No close phylogenetic relationship between the archaeal chaperonins and specific CCT subunits was observed, suggesting that none of the CCT gene duplications predate the divergence of archaea and eukaryotes. The duplications producing the CCTdelta and CCTepsilon subunits, as well as CCTalpha, CCTbeta, and CCTeta, are the most recent in the CCT gene family. Our analyses show significant differences in the rates of evolution of archaeal chaperonins compared with the eukaryotic CCTs, as well as among the different CCT subunits themselves. We discuss these results in light of current views on the origin, evolution, and function of CCT complexes.

Amino Acid Sequence↗

Environmental coupling of selection and heritability limits evolution.

There has recently been great interest in applying theoretical quantitative genetic models to empirical studies of evolution in wild populations. However, while classical models assume environmental constancy, most natural populations exist in variable environments. Here, we applied a novel analytical technique to a long-term study of birthweight in wild sheep and examined, for the first time, how variation in environmental quality simultaneously influences the strength of natural selection and the genetic basis of trait variability. In addition to demonstrating that selection and genetic variance vary dramatically across environments, our results show that environmental heterogeneity induces a negative correlation between these two parameters. Harsh environmental conditions were associated with strong selection for increased birthweight but low genetic variance, and vice versa. Consequently, the potential for microevolution in this population is constrained by either a lack of heritable variation (in poor environments) or by a reduced strength of selection (in good environments). More generally, environmental dependence of this nature may act to limit rates of evolution, maintain genetic variance, and favour phenotypic stasis in many natural systems. Assumptions of environmental constancy are likely to be violated in natural systems, and failure to acknowledge this may generate highly misleading expectations for phenotypic microevolution.

Animals↗

Unusual molecular evolution of an Adh pseudogene in Drosophila.

The Adh locus in Drosophila species which are members of the repleta group contains products of one or two duplication events. In all species examined to date one of the Adh genes is now a pseudogene, since mutations have rendered these genes incapable of being translated into a functional alcohol dehydrogenase. These pseudogenes contain introns in the standard Adh gene position; hence, their origin is not by retrotransposition. Comparison of the sequences of the Adh-psi from representatives of each of the subgroups of the repleta group reveal that the Adh pseudogene is present in each subgroup and that mutations at codon 2 and a deletion in the region immediately 5' to Adh-psi are common to all species. Therefore, it is likely that the translational inactivation event that resulted in a pseudogene occurred before the divergence of the species that make up the repleta group. We have investigated the transcription of Adh-psi of D. hydei and have found that the transcription has a developmental profile dissimilar from any known Adh gene, does not utilize an Adh promoter, and is initiated at a point almost 12 kb upstream. Comparison of sequence divergence of Adh-psi within species of the repleta group reveals that rates of evolution of the exons of Adh-psi are substantially slower than intergenic regions and are only slightly faster than those of exons of functional Adh genes. Second, retention of codon bias is found in the Adh-psi of most species, and substitution at synonymous coding positions substantially exceeds substitution at nonsynonymous coding positions. Comparison of the evolution of other putative pseudogenes with repleta group Adh pseudogenes suggests that at least some pseudogene sequences in Drosophila may be evolving through mechanisms and/or under influences not presently understood.

Alcohol Dehydrogenase↗

Evolution of EF-hand calcium-modulated proteins. II. Domains of several subfamilies have diverse evolutionary histories.

In the first report in this series we described the relationships and evolution of 152 individual proteins of the EF-hand subfamilies. Here we add 66 additional proteins and define eight (CDC, TPNV, CLNB, LPS, DGK, 1F8, VIS, TCBP) new subfamilies and seven (CAL, SQUD, CDPK, EFH5, TPP, LAV, CRGP) new unique proteins, which we assume represent new subfamilies. The main focus of this study is the classification of individual EF-hand domains. Five subfamilies--calmodulin, troponin C, essential light chain, regulatory light chain, CDC31/caltractin--and three uniques--call, squidulin, and calcium-dependent protein kinase--are congruent in that all evolved from a common four-domain precursor. In contrast calpain and sarcoplasmic calcium-binding protein (SARC) each evolved from its own one-domain precursor. The remaining 19 subfamilies and uniques appear to have evolved by translocation and splicing of genes encoding the EF-hand domains that were precursors to the congruent eight and to calpain and to SARC. The rates of evolution of the EF-hand domains are slower following formation of the subfamilies and establishment of their functions. Subfamilies are not readily classified by patterns of calcium coordination, interdomain linker stability, and glycine and proline distribution. There are many homoplasies indicating that similar variants of the EF-hand evolved by independent pathways.

Amino Acid Sequence↗

A time series of evolution in action: a latitudinal cline in wing size in South American Drosophila subobscura.

Drosophila subobscura is geographically widespread in the Old World. Around the late 1970s, it was accidentally introduced into both South and North America, where it spread rapidly over broad latitudinal ranges. This invading species offers opportunities to study the speed and predictability of trait evolution on a geographic scale. One trait of special interest is body size, which shows a strong and positive latitudinal cline in many Drosophila species, including Old World D. subobscura. Surveys made about a decade after the invasion found no evidence of a size cline in either North or South America. However, a survey made in North America about two decades after the invasion showed that a conspicuous size cline had evolved and (for females) was coincident with that for Old World flies. We have now conducted parallel studies on 10 populations (13 degrees of latitude) of flies, collected in Chile in spring 1999. After rearing flies in the laboratory for several generations, we measured wing sizes and compared geographic patterns (versus latitude or temperature) for flies on all three continents. South American females have now evolved a significant latitudinal size cline that is similar in slope to that of Old World and of North American flies. Rates of evolution (haldanes) for females are among the highest ever measured for quantitative traits. In contrast, the size cline is positive but not significant for South or North American males. At any given latitude, South American flies of both sexes are relatively large; this in part reflects the relatively cool climate of coastal Chile. Interestingly, the sections of the wing that generate the size cline for females differ among all three continents. Thus, although the evolution of overall wing size is predictable on a geographic scale (at least for females), the evolution of size of particular wing components is decidedly not.

Animals↗

The SPANX gene family of cancer/testis-specific antigens: rapid evolution and amplification in African great apes and hominids.

Human sperm protein associated with the nucleus on the X chromosome (SPANX) genes comprise a gene family with five known members (SPANX-A1, -A2, -B, -C, and -D), encoding cancer/testis-specific antigens that are potential targets for cancer immunotherapy. These highly similar paralogous genes cluster on the X chromosome at Xq27. We isolated and sequenced primate genomic clones homologous to human SPANX. Analysis of these clones and search of the human genome sequence revealed an uncharacterized group of genes, SPANX-N, which are present in all primates as well as in mouse and rat. In humans, four SPANX-N genes comprise a series of tandem duplicates at Xq27; a fifth member of this subfamily is located at Xp11. Similarly to SPANX-A/D, human SPANX-N genes are expressed in normal testis and some melanoma cell lines; testis-specific expression of SPANX is also conserved in mouse. Analysis of the taxonomic distribution of the long and short forms of the intron indicates that SPANX-N is the ancestral form, from which the SPANX-A/D subfamily evolved in the common ancestor of the hominoid lineage. Strikingly, the coding sequences of the SPANX genes evolved much faster than the intron and the 5' untranslated region. There is a strong correlation between the rates of evolution of synonymous and nonsynonymous codon positions, both of which are accelerated 2-fold or more compared to the noncoding sequences. Thus, evolution of the SPANX family appears to have involved positive selection that affected not only the protein sequence but also the synonymous sites in the coding sequence.

Amino Acid Sequence↗

Conflicting phylogenetic signals at the base of the metazoan tree.

A phylogenetic framework is essential for under-standing the origin and evolution of metazoan development. Despite a number of recent molecular studies and a rich fossil record of sponges and cnidarians, the evolutionary relationships of the early branching metazoan groups to each other and to a putative outgroup, the choanoflagellates, remain uncertain. This situation may be the result of the limited amount of phylogenetic information found in single genes and the small number of relevant taxa surveyed. To alleviate the effect of these analytical factors in the phylogenetic recons-truction of early branching metazoan lineages, we cloned multiple protein-coding genes from two choanoflagellates and diverse sponges, cnidarians, and a ctenophore. Comparisons of sequences for alpha-tubulin, beta-tubulin, elongation factor 2, HSP90, and HSP70 robustly support the hypothesis that choanoflagellates are closely affiliated with animals. However, analyses of single and concatenated amino acid sequences fail to resolve the relationships either between early branching metazoan groups or between Metazoa and choano-flagellates. We demonstrate that variable rates of evolution among lineages, sensitivity of the analyses to taxon selection, and conflicts in the phylogenetic signal contained in different amino acid sequences obscure the phylogenetic associations among the early branching Metazoa. These factors raise concerns about the ability to resolve the phylogenetic history of animals with molecular sequences. A consensus view of animal evolution may require investigations of genome-scale characters.

Animals↗

Evolution of thermal dependence of growth rate of Escherichia coli populations during 20,000 generations in a constant environment.

Twelve experimental populations of the bacterium Escherichia coli evolved for 20,000 generations in a defined medium at 37 degrees C. We measured their maximum growth rates across a broad range of temperatures and at several evolutionary time points to quantify the extent to which they became thermal specialists with diminished performance at other temperatures. We also sought to determine whether antagonistic pleiotropy (genetic trade-offs) or mutation accumulation (drift decay) was primarily responsible for any thermal specialization. Populations showed consistent improvement in growth rate at moderate temperatures (27-39 degrees C), but tended to have decreased growth rate at both low (20 degrees C) and high (41-42 degrees C) temperatures. Most loss occurred early in the experiment, when adaptation was most rapid. This dynamic is predicted by antagonistic pleiotropy but not by mutation accumulation. Several populations evolved high mutation rates due to defects in their DNA repair, but they did not subsequently undergo a greater decrease in growth rate at thermal extremes than populations that retained low mutation rates, contrary to the acceleration of decay predicted by mutation accumulation. Antagonistic pleiotropy therefore is more likely to be responsible for the evolution of thermal specialization observed in maximum growth rate.

Adaptation, Physiological↗

Evolution of lamivudine resistance in human immunodeficiency virus type 1-infected individuals: the relative roles of drift and selection.

Human immunodeficiency virus type 1 (HIV-1) rapidly develops resistance to lamivudine during monotherapy, typically resulting in the appearance at position 184 in reverse transcriptase (RT) of isoleucine instead of the wild-type methionine (M184I) early in therapy, which is later replaced by valine (M184V). M184V reduces viral susceptibility to drug in vitro by approximately 100-fold, but also results in a lower processivity of RT. We show that a drop in absolute viral fitness associated with the outgrowth of M184V results in a drop in viral load only in individuals with high CD4(+) counts, from whom we estimate the relative fitness of M184V in the presence of drug to be approximately 10% of that of the wild type prior to therapy. The timing of emergence of the M184V mutant varies widely between infected individuals. From analysis of the frequency of M184I and M184V mutants determined at multiple time points in seven individuals during lamivudine therapy, we estimated the fitness advantage of M184V over M184I during therapy to be approximately 23% on average. We have also estimated the average ratio of the frequencies of the two mutants prior to therapy to be 0. 2:1, with a range from 0.12:1 to 0.33:1. We have found that the differences between individuals in the rate of evolution of lamivudine resistance arise due to genetic drift affecting the relative frequency of M184I and M184V prior to therapy. These results show that stochastic effects can be significant in HIV evolution, even when there is large fitness difference between mutant and wild-type variants.

Anti-HIV Agents↗

Phylogeny of Bicyclus (Lepidoptera: Nymphalidae) inferred from COI, COII, and EF-1alpha gene sequences.

Despite the fact that Bicyclus anynana has become an important model species for wing-pattern developmental biology and studies of phenotypic plasticity, little is known of the evolutionary history of the genus Bicyclus and the position of B. anynana. Understanding the evolution of development as well as the evolution of plasticity can be attempted in this species-rich genus that displays a large range of wing patterns with variable degrees of phenotypic responses to the environment. A context to guide extrapolations from population genetic studies within B. anynana to those between closely related species has been long overdue. A phylogeny of 54 of the 80 known Bicyclus species is presented based on the combined 3000-bp sequences of two mitochondrial genes, cytochrome oxidase I and II, and the nuclear gene, elongation factor 1alpha. A series of tree topologies, constructed either from the individual genes or from the combined data, using heuristic searches under a variety of weighting schemes were compared under the best maximum-likelihood models fitted for each gene separately. The most likely tree topology to have generated the three data sets was found to be a tree resulting from a combined MP analysis with equal weights. Most phylogenetic signal for the analysis comes from silent substitutions at the third position, and despite the faster rate of evolution and higher levels of homoplasy of the mitochondrial genes relative to the nuclear gene, the latter does not show substantially stronger support for basal clades. Finally, moving branches from the chosen tree topology to other positions on the tree so as to comply better with a previous morphological study did not significantly affect tree length.

Animals↗

Escape from evolutionary stasis by transposon-mediated deleterious mutations.

Evolution within a rugged fitness landscape is limited by the tendency for organisms to become trapped on local optima resulting in evolutionary stasis. It is presently unclear how founder populations escape from an adaptive peak to found a new species. Insertion sequences, transposons and other mobile DNA elements are found in all species of eukaryotes, bacteria and archaebacteria, where they have been sought and are usually considered to be genomic parasites or selfish genes. However, many transposons and other mobile repetitive DNA are remarkably species or phyla-specific, indicating that infection with transposable elements coincides with speciation events and is involved in promoting evolutionary change. We propose here a model in which transposable elements are involved in speciation events by their ability to produce irreversible deleterious mutations that promote escape from evolutionary stasis. We have constructed a genetic algorithm designed to model both spontaneous and transposon-mediated mutations in populations of asexual digital organisms. We use this model to investigate the effect of transposon-mediated mutations on the rate of evolution of digital organisms as they compete for resources within an artificial adaptive landscape. In the absence of transposon mutations the seed organisms quickly evolve to occupy the nearest adaptive peak but thereafter evolutionary stasis ensues and adjacent empty peaks are left unoccupied. In the presence of transposon mutations, evolution is again dominated by stasis but is punctuated by bursts of rapid evolution in with consecutive unoccupied adaptive peaks are filled with organisms derived from single transposition events. Rapid evolutionary events leading to founding of new biological species, may be similarly initiated by irreversible deleterious mutations induced by transposition.

Adaptation, Physiological↗

V3 seroreactivity and sequence variation: tracking the emergence of V3 genotypic variation in HIV-1-infected patients.

OBJECTIVE: To investigate the relationship between V3-specific immune responses and viral quasispecies evolution in 10 HIV-1-seropositive patients enrolled in a phase I trial of recombinant gp160. METHODS: Serologic responses to the HIVLAI V3 loop and autologous V3 loop DNA sequences were sequentially determined over a 3-4-year interval. RESULTS: Six patients either seroconverted or had a > or = 42-fold boost in titer to the V3 reagent associated with an average of 3.2 amino-acid changes in their autologous V3 loops. Four patients with < or = 11-fold change in titer to the V3 loop showed an average of 0.75 amino-acid changes. Attempts to measure autologous V3 loop responses in four patients using a peptide enzyme-linked immunosorbent assay technique did not show a distinct binding preference for autologous versus heterologous V3 loop peptides. Thus, we interpret seroreactivity to the heterologous HIVLAI V3 loop to reflect the broadness of the V3 immune response rather than a direct measure of epitope-specific immune pressure. CONCLUSIONS: These data suggest that the broadness of serologic responses to viral epitopes are reflected in the rate of evolution of their cognate coding sequences and support the view that the immune response to HIV-1 results in the continuous selection of new viral variants during the course of disease.

AIDS Vaccines↗

Structure and evolution of the apolipoprotein multigene family.

We present the complementary DNA and deduced amino acid sequence of rat apolipoprotein A-II (apoA-II), and the results of a detailed statistical analysis of the nucleotide and amino acid sequences of all the apolipoprotein gene sequences published to date: namely, those of human and rat apoA-I, apoA-II and apoE, rat apoA-IV, and human apoC-I, C-II and C-III. Our results indicate that the apolipoprotein genes have very similar genomic structures, each having a total of three introns at the same locations. Using the exon/intron junctions as reference points, we have obtained an alignment of the coding regions of all the genes studied. It appears that the mature peptide regions of these genes are almost completely made up of tandem repeats of 11 codons. The part of mature peptide region encoded by exon 3 contains a common block of 33 codons, whereas the part encoded by exon 4 contains a much more variable number of internal repeats of 11 codons. These genes have apparently evolved from a primordial gene through multiple partial (internal) and complete gene duplications. On the basis of the degree of homology of the various sequences, and the pattern of the internal repeats in these genes, we propose an evolutionary tree for the apolipoprotein genes and give rough estimates of the divergence times between these genes. Our results show that apoA-II has evolved extremely rapidly and that apoA-I and apoE also have evolved at high rates but some regions are better conserved than the others. The rate of evolution of individual regions seems to be related to the stringency of their functional requirements.

Amino Acid Sequence↗

Fast protein evolution and germ line expression of a Drosophila parental gene and its young retroposed paralog.

This is the first detailed study of the evolution, phylogenetic distribution, and transcription of one young retroposed gene, CG13732, and its parental gene CG15645, whose functions are unknown. CG13732 is a recognizable retroposed copy of CG15645 retaining the signals of this process. We name the parental gene Cervantes and the retrogene Quijote. To determine when this duplication occurred and the phylogenetic distribution of Quijote, we employed polymerase chain reaction, Southern blotting, and the available information on sequenced Drosophila genomes. Interestingly, these analyses revealed that Quijote is present only in 4 species of Drosophila (Drosophila melanogaster, Drosophila simulans, Drosophila sechellia, and Drosophila mauritiana) and that retroposed copies of Cervantes have also originated in the lineages leading to Drosophila yakuba and Drosophila erecta independently in the 3 instances. We name the new retrogene in the D. yakuba lineage Rocinante and the new retrogene in the D. erecta lineage Sancho. In this work, we present data on Quijote and its parental gene Cervantes. Polymorphism analysis of the derived gene and divergence data for both parental and derived genes were used to determine that both genes likely produce functional proteins and that they are changing at a fast rate (KA/KS approximately 0.38). The negative value of H of Fay and Wu in the non-African sample reveals an excess of derived variants at high frequency. This could be explained either by positive selection in the region or by demographic effects. The comparative expression pattern shows that both genes express in the same adult tissues (male and female germ line) in D. melanogaster. Quijote is also expressed in male and female in D. simulans, D. sechellia, and D. mauritiana. We argue that the fast rate of evolution of these genes could be related to their putative germ line function and are further studying the independent recruitment of Cervantes-derived retrogenes in multiple lineages.

Animals↗