Xenbase Image ID: 153329
Figure 3. Structural response to allotetraploidya. Distributions of consecutive retentions (left) and deletions (right) in the L (red) and S (blue) subgenomes. The distributions were fit using the equation y= a*(ebx) + c*(edx). The y-axis is shown on a log scale. Significant differences were seen between L and S subgenomes in both distributions (Student’s t-test, retention p=3.6E-22, deletion p=4.5E-84).b. Evolutionary conservation of the Xenopus MHC and differential MHC silencing on the two X. laevis subgenomes. Selected gene names shown above. The ‘Adaptive MHC’ encodes tightly-linked essential genes involved in antigen presentation to T cells; this group of genes is the primordial linkage group and has been preserved in most non-mammalian vertebrates, including Xenopus. Differential gene silencing is particularly pronounced as four genes around the class I gene are functional on S chromosome but absent (dma, dmb) or pseudogenes (ring3, lmp2) on L chromosome. The gene map is not to scale; pseudogenes (p) are noted as indicated. HSA, XLA, GGA: human, Xenopus, and chicken MHC, respectively. Refer to the Supplemental Table 8 for a more detailed MHC map.c. Hox gene clusters. X. laevis retains eight Hox clusters, consisting of pairs of HoxA, B, C and D clusters, on L and S chromosomes. even-skipped genes (evx1 or evx2) are positioned flanking Hoxa and Hoxd clusters. hox genes are classified into four, labial, proboscipedia, central, and posterior groups. Note that hoxb2.L (black) is a pseudogene.d. Syntenies around the mix gene family. Abbreviations for species and chromosome numbers: human (H. sapiens; HSA1), chicken (G. gallus; GGA3), X. tropicalis (XTR5), X. laevis (XLA5L and XLA5S), zebrafish (D. rerio; DRE20). Each Xenopus (sub)genome experienced its own independent expansion of the family (see Extended Data Fig. 5 for details).
Image published in: Session AM et al. (2016)
Image downloaded from an Open Access article in PubMed Central. Image reproduced on Xenbase with permission of the publisher and the copyright holder.
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