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PubMed1990

Analysis of naturally occurring deletion variants of African swine fever virus: multigene family 110 is not essential for infectivity or virulence in pigs.

A comparison of uncloned African swine fever virus isolates with their cloned counterparts revealed the presence of genetic variants in three out of seven uncloned field virus populations tested. Five different virus clones were isolated from the uncloned KIR69 virus stock by limit dilution. Structural analysis of the variants showed that they differed by single deletions of 10-16 kilobases in the region located between 6.8 and 27 kilobases from the left DNA terminus. There was no homology between DNA sequences immediately to the left and right of the deletions indicating that the mechanism generating deletion variants was not homologous recombination. The alignment of the restriction maps of the variants with those of other virus isolates indicated that two of the variants lacked the whole multigene family 110. This was confirmed by hybridization of the viral DNA with a degenerate oligonucleotide probe. Each virus variant replicated to high titer and was virulent in domestic pigs. Therefore, the multigene family 110 was not required for viral replication or virulence in domestic pigs. The virus variants were stable upon repeated passage in swine macrophages, indicating that the generation of variants is not a frequent genetic event in vitro.

African Swine Fever↗

PubMed1991

Characterization of a murine cDNA encoding a member of the carboxylesterase multigene family.

We have characterized a mRNA sequence containing the entire coding region of a mouse carboxylesterase (EC 3.1.1.1). pEs-N, an 1840-bp composite of five overlapping cDNA clones, contains an open reading frame of 554 amino acids that display a high degree of similarity with rat and rabbit carboxylesterases. Genetic mapping studies place this carboxylesterase in cluster 1 of the esterase region on chromosome 8. Results of blot hybridization analysis of genomic DNA probed with a pEs-N cDNA under both low and high stringency conditions suggest membership in a carboxylesterase multigene family, as would be expected for a nonspecific carboxylesterase. A message size of 1850-1900 nucleotides was revealed by RNA blot hybridization analysis. S1 nuclease protection analyses with a probe representing a segment of pEs-N detected message in liver, kidney, and lung, but not in spleen, brain, testes, and submandibular gland, with higher levels in female than in male kidney. Additional S1 nuclease-protected mRNA species were found, suggesting the expression of distinct members of a multigene family. In vitro translation of a full-size transcript of pEs-N resulted in a product of 51.5 kDa. Upon the addition of microsomes, this product was processed into a protein of 60.4 kDa, which is within the size range of monomeric units of mouse carboxylesterases.

Amino Acid Sequence↗

PubMed1988

Replication program of active and inactive multigene families in mammalian cells.

In a comprehensive study, the temporal replication of tissue-specific genes and flanking sequences was compared in nine cell lines exhibiting different tissue-specific functions. Some of the rules we have determined for the replication of these tissue specific genes include the following. (i) Actively transcribed genes usually replicate during the first quarter of the S phase. (ii) Some immunoglobulin genes replicate during the first half of S phase even when no transcriptional activity is detected but appear to replicate even earlier in cell lines where they are transcribed. (iii) Nontranscribed genes can replicate during any interval of S phase. (iv) Multigene families arranged in clusters of 250 kilobases or less define a temporal compartment comprising approximately one-quarter of S phase. While these rules, and others that are discussed, apply to the tissue-specific genes studied here, all tissue-specific genes may not follow this pattern. In addition, housekeeping genes did not follow some of these rules. These results provide the first molecular evidence that the coordinate timing of replication of contiguous sequences within a multigene family is a general property of the mammalian genome. The relationship between replication very early during S phase and the transcriptional activity within a chromosomal domain is discussed.

Animals↗

PubMed1990

Chromosomal location of the Ly-49 (A1, YE1/48) multigene family. Genetic association with the NK 1.1 antigen.

The Ly-49 (A1, YE1/48) Ag is a disulfide-linked dimer with 44-kDa subunits, and is expressed on the cell surface of rare T cell tumors of C57BL/6 origin. Although this Ag is undetectable by flow microfluorimetry analysis, normal cells have been shown to express the A1 Ag by immunoprecipitation experiments performed on surface radioiodinated spleen and thymus cells. We (J. Immunol. 143:1379, 1989) and others (J. Immunol. 142:1727, 1989) have recently isolated cDNA encoding the Ly-49 Ag. Southern blots with an Ly-49 cDNA probe revealed multiple bands, consistent with cross-hybridization to other members of a multigene family, and significant RFLP between the C57BL/6 and BALB/c strains. When the RFLP patterns displayed by other common laboratory strains as well as informative recombinant inbred strains were examined, the Ly-49 gene family displayed five RFLP patterns and the entire family was found to reside on a contiguous stretch of the distal portion of mouse chromosome 6, the same region to which the NK1.1 Ag has been mapped. Although tissue distribution studies and transfection analysis ruled out the possibility that Ly-49 was identical to NK1.1 Ag, approximately 20% of NK1.1 cells isolated from normal spleen coexpressed Ly-49 and all Ly-49+ cells were CD3-. Although spleen cells cultured in high doses of rIL-2 demonstrated similar coexpression of NK1.1 and Ly-49, approximately 10% of CD3+ cells coexpressed Ly-49. The chromosomal mapping data and the expression of the Ly-49 and NK1.1 Ag suggest that the NK1.1 Ag may be a member of the Ly-49 multigene family.

Animals↗

PubMed1995

cDNA cloning and characterization of rat salivary glycoproteins. Novel members of the proline-rich-protein multigene families.

The cDNAs for two glycoproteins, the 158-kDa submandibular glycoprotein (SGP158) and the 200-kDa parotid glycoprotein (PGP200), have been cloned from rat submandibular and parotid glands, respectively. Both cDNAs encode for identical proteins with repeating peptides -Asp-Gln-Gly-(Asn)-Gln-Thr-Gln-Pro-Arg-Pro-Pro-His-Pro-. A full-length cDNA encoding SGP158 was obtained using the strategy of anchor-PCR, and a full-length cDNA of PGP200 was prepared using RNA-PCR. Sequence analysis of the cDNAs revealed that SGP158 and PGP200 are identical proteins with 23 repeating peptides. Twenty-one peptides contain potential N-glycosylation sites and these two glycoproteins differ only in their glycosylation patterns. Southern-blot analysis showed that a single-copy gene encodes both mRNAs. PGP200 is constitutively expressed, but the synthesis of SGP158 is totally dependent upon treatment of animals with the beta-agonist isoproterenol. The first 106-nucleotide sequence of cDNAs for PGP200 and SGP158, which corresponds to the 5'-untranslated region and sequence encoding the signal peptide, is highly conserved when compared with proline-rich protein and glutamine-rich protein gene sequences. Based on the nucleotide sequences of exon I, a phylogenetic tree was constructed for 35 members of these multigene families. The tree fits with the generally recognized phylogeny of mammalian orders. We propose that exon I sequences of the proline-rich protein and glutamine-rich protein multigene families are relatively new and are possibly generated through exon shuffling during evolution.

Amino Acid Sequence↗

PubMed2004

Chicken Ig-like receptor B2, a member of a multigene family, is mainly expressed on B lymphocytes, recruits both Src homology 2 domain containing protein tyrosine phosphatase (SHP)-1 and SHP-2, and inhibits proliferation.

Ig-like inhibitory receptors have been the focus of intensive research particularly in mouse and human. We report the cloning and characterization of three novel inhibitory chicken Ig-like receptors (CHIR) that display a two Ig-domain extracellular structure, a transmembrane region lacking charged residues and a cytoplasmic domain containing two ITIM. The localization of all receptors to a small genomic region and the hybridization pattern indicated that they belong to a multigene family. The genomic structure of the extracellular domain with two exons encoding the signal peptide and single exons for each Ig domain resembled that of all human leukocyte Ig-like receptors and killer cell Ig-like receptors, whereas the exons encoding the C terminus displayed a structure closely resembling killer cell Ig-like receptor genes. A mAb generated against one receptor designated CHIR-B2 reacted with all B cells and a small T cell subset, but not with monocytes, thrombocytes, or various leukocyte-derived cell lines. The mAb immunoprecipitated a 46-kDa protein from bursal cells and transfected cells. The Src homology 2 domain containing protein tyrosine phosphatase (SHP)-2 bound to CHIR-B2 even in unstimulated cells, whereas pervanadate treatment induced the tyrosine phosphorylation and recruitment of several CHIR-B2-associated proteins including SHP-1 and increased levels of SHP-2. Moreover, mAb cross-linking of CHIR-B2 reduced the proliferation of a stable transfected cell line. Together, we have identified a multigene family containing multiple CHIR including one receptor designated CHIR-B2 that is mainly expressed on B lymphocytes and inhibits cellular proliferation by recruitment of SHP-1 and SHP-2.

Amino Acid Sequence↗

PubMed1989

SSC1, an essential member of the yeast HSP70 multigene family, encodes a mitochondrial protein.

SSC1 is an essential member of the yeast HSP70 multigene family (E. Craig, J. Kramer, and J. Kosic-Smithers, Proc. Natl. Acad. Sci. USA 84:4156-4160, 1987). Analysis of the SSC1 DNA sequence revealed that it could encode a 70,627-dalton protein that is more similar to DnaK, an Escherichia coli hsp70 protein, than other yeast hsp70s whose sequences have been determined. Ssc1p was found to have an amino-terminal extension of 28 amino acids, in comparison with either Ssa1p, another hsp70 yeast protein, or Dnak. This putative leader is rich in basic and hydroxyl amino acids, characteristic of many mitochondrial leader sequences. Ssc1p that was synthesized in vitro could be imported into mitochondria and was cleaved in the process. The imported protein comigrated with an abundant mitochondrial protein that reacted with hsp70-specific antibodies. We conclude that Ssc1p is a mitochondrial protein and that hsp70 proteins perform functions in many compartments of the cell.

Amino Acid Sequence↗

PubMed1990

DNA sequence evolution of the amylase multigene family in Drosophila pseudoobscura.

The alpha-Amylase locus in Drosophila pseudoobscura is a multigene family of one, two or three copies on the third chromosome. The nucleotide sequences of the three Amylase genes from a single chromosome of D. pseudoobscura are presented. The three Amylase genes differ at about 0.5% of their nucleotides. Each gene has a putative intron of 71 (Amy1) or 81 (Amy2 and Amy3) bp. In contrast, Drosophila melanogaster Amylase genes do not have an intron. The functional Amy1 gene of D. pseudoobscura differs from the Amy-p1 gene of D. melanogaster at an estimated 13.3% of the 1482 nucleotides in the coding region. The estimated rate of synonymous substitutions is 0.398 +/- 0.043, and the estimated rate of nonsynonymous substitutions is 0.068 +/- 0.008. From the sequence data we infer that Amy2 and Amy3 are more closely related to each other than either is to Amy1. From the pattern of nucleotide substitutions we reason that there is selection against synonymous substitutions within the Amy1 sequence; that there is selection against nonsynonymous substitutions within the Amy2 sequence, or that Amy2 has recently undergone a gene conversion with Amy1; and that Amy3 is nonfunctional and subject to random genetic drift.

Amylases↗

PubMed1984

Some models of gene conversion for treating the evolution of multigene families.

A simple model of gene conversion presented earlier has been compared with a more general model under the assumption of no bias. The former is based on a simple concept that, by conversion, a gene (or a segment of a gene) is transferred from one locus to another in a multigene family. Intrachromatid symmetric conversion may result in reciprocal exchange of genes within a multigene family, and the previous theory of identity coefficients needs modification when it occurs. The relationship of various parameters of the two models was made clear in formulating the transition equations of identity coefficients. As an example of extending the analyses, a model of preferential conversion that is relevant to the observed uneven polymorphisms of class I genes in the major histocompatibility complex has been investigated. It differs from the biased conversion, in that directional process is through location of genes on the chromosome. It is shown that the model satisfactorily explains the observed data, even though the effect of preferential conversion is difficult to distinguish from that of natural selection.

Biological Evolution↗

PubMed1995

Molecular cloning and sequence analysis of expansins--a highly conserved, multigene family of proteins that mediate cell wall extension in plants.

Expansins are unusual proteins discovered by virtue of their ability to mediate cell wall extension in plants. We identified cDNA clones for two cucumber expansins on the basis of peptide sequences of proteins purified from cucumber hypocotyls. The expansin cDNAs encode related proteins with signal peptides predicted to direct protein secretion to the cell wall. Northern blot analysis showed moderate transcript abundance in the growing region of the hypocotyl and no detectable transcripts in the nongrowing region. Rice and Arabidopsis expansin cDNAs were identified from collections of anonymous cDNAs (expressed sequence tags). Sequence comparisons indicate at least four distinct expansin cDNAs in rice and at least six in Arabidopsis. Expansins are highly conserved in size and sequence (60-87% amino acid sequence identity and 75-95% similarity between any pairwise comparison), and phylogenetic trees indicate that this multigene family formed before the evolutionary divergence of monocotyledons and dicotyledons. Sequence and motif analyses show no similarities to known functional domains that might account for expansin action on wall extension. A series of highly conserved tryptophans may function in expansin binding to cellulose or other glycans. The high conservation of this multigene family indicates that the mechanism by which expansins promote wall extensin tolerates little variation in protein structure.

Amino Acid Sequence↗

PubMed2004

African swine fever virus multigene family 360 and 530 genes affect host interferon response.

African swine fever virus (ASFV) multigene family 360 and 530 (MGF360/530) genes affect viral growth in macrophage cell cultures and virulence in pigs (L. Zsak, Z. Lu, T. G. Burrage, J. G. Neilan, G. F. Kutish, D. M. Moore, and D. L. Rock, J. Virol. 75:3066-3076, 2001). The mechanism by which these novel genes affect virus-host interactions is unknown. To define MGF360/530 gene function, we compared macrophage transcriptional responses following infection with parental ASFV (Pr4) and an MGF360/530 deletion mutant (Pr4 Delta 35). A swine cDNA microarray containing 7,712 macrophage cDNA clones was used to compare the transcriptional profiles of swine macrophages infected with Pr4 and Pr4 Delta 35 at 3 and 6 h postinfection (hpi). While at 3 hpi most (7,564) of the genes had similar expression levels in cells infected with either virus, 38 genes had significantly increased (>2.0-fold, P < 0.05) mRNA levels in Pr4 Delta 35-infected macrophages. Similar up-regulation of these genes was observed at 6 hpi. Viral infection was required for this induced transcriptional response. Most Pr Delta 35 up-regulated genes were part of a type I interferon (IFN) response or were genes that are normally induced by double-stranded RNA and/or viral infection. These included monocyte chemoattractant protein, transmembrane protein 3, tetratricopeptide repeat protein 1, a ubiquitin-like 17-kDa protein, ubiquitin-specific protease ISG43, an RNA helicase DEAD box protein, GTP-binding MX protein, the cytokine IP-10, and the PKR activator PACT. Differential expression of IFN early-response genes in Pr4 Delta 35 relative to Pr4 was confirmed by Northern blot analysis and real-time PCR. Analysis of IFN-alpha mRNA and secreted IFN-alpha levels at 3, 8, and 24 hpi revealed undetectable IFN-alpha in mock- and Pr4-infected macrophages but significant IFN-alpha levels at 24 hpi in Pr4 Delta 35-infected macrophages. The absence of IFN-alpha in Pr4-infected macrophages suggests that MGF360/530 genes either directly or indirectly suppress a type I IFN response. An inability to suppress host type I IFN responses may account for the growth defect of Pr4 Delta 35 in macrophages and its attenuation in swine.

African Swine Fever↗

PubMed1998

Major antigenic proteins of the agent of human granulocytic ehrlichiosis are encoded by members of a multigene family.

Western blot analysis of proteins from a cell culture isolate (USG3) of the human granulocytic ehrlichiosis (HGE) agent has identified a number of immunoreactive proteins, including major antigenic proteins of 43 and 45 kDa. Peptides derived from the 43- and 45-kDa proteins were sequenced, and degenerate PCR primers based on these sequences were used to amplify DNA from USG3. Sequencing of a 550-bp PCR product revealed that it encodes a protein homologous to the MSP-2 proteins of Anaplasma marginale. Concurrently, an expression library made from USG3 genomic DNA was screened with granulocytic Ehrlichia (GE)-positive immune sera. Analysis of two clones showed that they contain one partial and three full-length highly related genes, suggesting that they are part of a multigene family. Amino acid alignment showed conserved amino- and carboxy-terminal regions which flank a variable region. The conserved regions of these proteins are also homologous to the MSP-2 proteins of A. marginale; thus, they were designated GE MSP-2A (45 kDa), MSP-2B (34 kDa), and MSP-2C (38 kDa). The PCR fragment obtained as a result of peptide sequencing was completely contained within the msp-2A clone, and all of the sequenced peptides were found in the GE MSP-2 proteins. Recombinant MSP-2B protein and an MSP-2A fusion protein were expressed in Escherichia coli and reacted with human sera positive for the HGE agent by immunofluorescence assay. These data suggest that the 43- and 45-kDa proteins of the HGE agent are encoded by members of the GE MSP-2 multigene family.

Amino Acid Sequence↗

PubMed2002

Evolution of the sulfide-binding function within the globin multigenic family of the deep-sea hydrothermal vent tubeworm Riftia pachyptila.

The giant extracellular hexagonal bilayer hemoglobin (HBL-Hb) of the deep-sea hydrothermal vent tube worm Riftia pachyptila is able to transport simultaneously O(2) and H(2)S in the blood from the gills to a specific organ: the trophosome that harbors sulfide-oxidizing endosymbionts. This vascular HBL-Hb is made of 144 globins from which four globin types (A1, A2, B1, and B2) coevolve. The H(2)S is bound at a specific location (not on the heme site) onto two of these globin types. In order to understand how such a function emerged and evolved in vestimentiferans and other related annelids, six partial cDNAs corresponding to the six globins known to compose the multigenic family of R. pachyptila have been identified and sequenced. These partial sequences (ca. 120 amino acids, i.e., 80% of the entire protein) were used to reconstruct molecular phylogenies in order to trace duplication events that have led to the family organization of these globins and to locate the position of the free cysteine residues known to bind H(2)S. From these sequences, only two free cysteine residues have been found to occur, at positions Cys + 1 (i.e., 1 a.a. from the well-conserved distal histidine) and Cys + 11 (i.e., 11 a.a. from the same histidine) in globins B2 and A2, respectively. These two positions are well conserved in annelids, vestimentiferans, and pogonophorans, which live in sulfidic environments. The structural comparison of the hydrophobic environment that surrounds these cysteine residues (the sulfide-binding domain) using hydrophobic cluster analysis plots, together with the cysteine positions in paralogous strains, suggests that the sulfide-binding function might have emerged before the annelid radiation in order to detoxify this toxic compound. Moreover, globin evolutionary rates are highly different between paralogous strains. This suggests that either the two globin subfamilies involved in the sulfide-binding function (A2 and B2) have evolved under strong directional selective constraints (negative selection) and that the two other globins (A1 and B1) have accumulated more substitutions through positive selection or have evolved neutrally after a relaxation of selection pressures. A likely scenario on the evolution of this multigenic family is proposed and discussed from this data set.

Amino Acid Sequence↗

PubMed1986

Anomalous placement of introns in a member of the intermediate filament multigene family: an evolutionary conundrum.

The origin of introns and their role (if any) in gene expression, in the evolution of the genome, and in the generation of new expressed sequences are issues that are understood poorly, if at all. Multigene families provide a favorable opportunity for examining the evolutionary history of introns because it is possible to identify changes in intron placement and content since the divergence of family members from a common ancestral sequence. Here we report the complete sequence of the gene encoding the 68-kilodalton (kDa) neurofilament protein; the gene is a member of the intermediate filament multigene family that diverged over 600 million years ago. Five other members of this family (desmin, vimentin, glial fibrillary acidic protein, and type I and type II keratins) are encoded by genes with six or more introns at homologous positions. To our surprise, the number and placement of introns in the 68-kDa neurofilament protein gene were completely anomalous, with only three introns, none of which corresponded in position to introns in any characterized intermediate filament gene. This finding was all the more unexpected because comparative amino acid sequence data suggest a closer relationship of the 68-kDa neurofilament protein to desmin, vimentin, and glial fibrillary acidic protein than between any of these three proteins and the keratins. It appears likely that an mRNA-mediated transposition event was involved in the evolution of the 68-kDa neurofilament protein gene and that subsequent events led to the acquisition of at least two of the three introns present in the contemporary sequence.

Amino Acid Sequence↗

PubMed1983

Genetic exchanges between partially homologous nucleotide sequences: possible implications for multigene families.

Many sequences, particularly in the genome of the higher eukaryotes, are reiterated several or many times, but are only partially homologous. It is commonly accepted that such sequences (for example, genes of a multigene family) may, on occasions, undergo reciprocal and non-reciprocal genetic exchanges by crossing-over or gene conversion. This relies on the implicit assumption that partially homologous sequences may pair to form heteroduplex structures. We discuss the possibility that correction of such heteroduplexes into homoduplexes may be a common genetic mechanism with significant evolutionary importance, particularly in the higher eukaryotes: it provides a basis for a novel source of point and non point mutation and a means of generating many variations in a gene sequence in a single step. We also emphasize the possible role of non coding nucleotides, particularly introns, in permitting (when conserved) or blocking (when divergent) such exchanges between members of a multigene family.

Animals↗

PubMed1983

Evolutionary history of a multigene family: an expressed human beta-tubulin gene and three processed pseudogenes.

A 3' untranslated region subclone from a human beta-tubulin cDNA clone has been used to dissect the human beta-tubulin multigene family. Four different beta-tubulin sequences were obtained. One consists of an expressed gene that yields two mRNA species of 1.8 kb and 2.6 kb as a consequence of alternative polyadenylation sites. The three remaining beta-tubulin sequences are all intronless pseudogenes, each containing a 3' poly(A) tract downstream from the poly(A) signal, and each flanked by a different short direct repeat. Two of these sequences were derived by integration into the host germ line of cDNA copies of the 1.8 kb mRNA; the third was derived from the 2.6 kb mRNA. Comparison of the functional and nonfunctional sequences suggests that the integration events took place 4, 10, and 13 million years ago. We anticipate that, in multigene families where germ-line expression occurs, a significant portion of sequences will be accounted for by pseudogenes generated via an RNA intermediate.

Amino Acid Sequence↗

PubMed2005

Multigenic families and proteomics: extended protein characterization as a tool for paralog gene identification.

In classical proteomic studies, the searches in protein databases lead mostly to the identification of protein functions by homology due to the non-exhaustiveness of the protein databases. The quality of the identification depends on the studied organism, its complexity and its representation in the protein databases. Nevertheless, this basic function identification is insufficient for certain applications namely for the development of RNA-based gene-silencing strategies, commonly termed RNA interference (RNAi) in animals and post-transcriptional gene silencing (PTGS) in plants, that require an unambiguous identification of the targeted gene sequence. A PTGS strategy was considered in the study of the infection of Oryza sativa by the Rice Yellow Mottle Virus (RYMV). It is suspected that the RYMV recruits host proteins after its entry into plant cells to form a complex facilitating virus multiplication and spreading. The protein partners of this complex were identified by a classical proteomic approach, nano liquid chromatography tandem mass spectrometry. Among the identified proteins, several were retained for a PTGS strategy. Nevertheless most of the protein candidates appear to be members of multigenic families for which all paralog genes are not present in protein databases. Thus the identification of the real expressed paralog gene with classical protein database searches is impossible. Consequently, as the genome contains all genes and thus all paralog genes, a whole genome search strategy was developed to determine the specific expressed paralog gene. With this approach, the identification of peptides matching only a single gene, called discriminant peptides, allows definitive proof of the expression of this identified gene. This strategy has several requirements: (i) a genome completely sequenced and accessible; (ii) high protein sequence coverage. In the present work, through three examples, we report and validate for the first time a genome database search strategy to specifically identify paralog genes belonging to multigenic families expressed under specific conditions.

Chaperonin 60↗

PubMed1989

Cloning and molecular characterization of the chalcone synthase multigene family of Petunia hybrida.

Chalcone synthase-encoding genes (chs) in Petunia hybrida comprise a multigene family. Some of the chs genes have been grouped into a subfamily, based upon their strong cross-hybridization and tight genomic linkage. From genomic libraries eight 'complete' chs genes, two chs gene 5'-fragments and two chs gene 3'-fragments have been isolated. The nucleotide sequence of six complete chs genes is presented and discussed in relation to their evolutionary origin and expression in different tissues. Each member of the family consists of two exons separated by an intron of variable size and sequence, which is located at a conserved position. The chs gene fragments represent single exons. Homology between non-linked chs genes is approx. 80% at the DNA level and restricted to protein-coding sequences. Homology between subfamily members (which are tightly linked) is higher (90-99%) and extends into untranslated regions of the gene, strengthening the view that they arose by recent gene duplications. The chsD gene contains a mutated translation stop codon, suggesting that this is an inactive (pseudo)gene. None of the other members of the gene family exhibits characteristics of a pseudogene, indicating that if gene inactivation has occurred during their evolution, it must characteristics of a pseudogene, indicating that if gene inactivation has occurred during their evolution, it must have been a recent event. Homology at the protein level between some (expressed) chs genes is surprisingly low. The possibility that these genes encode proteins with slightly different enzymatic activities is discussed.

Acyltransferases↗