Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution: II. Polycondensations

Kolb, Vera M.; Orgel, Leslie E.

doi:10.1007/bf00167106

Cited by 4 publications

(1 citation statement)

References 17 publications

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“…This is the key restriction in the design of the alternative genetic materials. The precipitation limitation was also found in some other prebiotic polymerizations 31,32 . We thus need the experimental verification of the usefulness of any proposed monomers: if the polymer precipitates prematurely, the otherwise good monomer is of a limited use.…”

Section: Chemical Criteria For the Life That Is Substantially Differementioning

confidence: 55%

Living strategies of unusual life forms on Earth and the relevance to astrobiology

Liesch

Kolb

2007

Instruments, Methods, and Missions for Astrobiology X

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In this paper we discuss the astrobiological importance of various viruses, nanobacteria, Archaea and bacteria. Viruses and nanobacteria challenge the current definitions of life, but we consider them here as life forms. Nanobacteria have interesting mode of fossilization and have a potential for creating biosignatures. Archaea and some bacteria make unique lipid-related compounds that can be used as biosignatures. We focus on the organisms and life forms that seem to be well suited for the life on Mars or other extraterrestrial environments that are harsh. Many of these organisms and life forms share their genetic material freely with other organisms and species. Such an altruistic approach may have been typical for the early life on Earth.

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Section: Chemical Criteria For the Life That Is Substantially Differementioning

confidence: 55%

Living strategies of unusual life forms on Earth and the relevance to astrobiology

Liesch

Kolb

2007

Instruments, Methods, and Missions for Astrobiology X

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The diversity and evolutionary relationships of the pregnancy-associated glycoproteins, an aspartic proteinase subfamily consisting of many trophoblast-expressed genes

Xie

Green

Bixby

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

157

134

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The pregnancy-associated glycoproteins (PAGs) are structurally related to the pepsins, thought to be restricted to the hooved (ungulate) mammals and characterized by being expressed specifically in the outer epithelial cell layer (chorion͞trophectoderm) of the placenta. At least some PAGs are catalytically inactive as proteinases, although each appears to possess a cleft capable of binding peptides. By cloning expressed genes from ovine and bovine placental cDNA libraries, by Southern genomic blotting, by screening genomic libraries, and by using PCR to amplify portions of PAG genes from genomic DNA, we estimate that cattle, sheep, and most probably all ruminant Artiodactyla possess many, possibly 100 or more, PAG genes, many of which are placentally expressed. The PAGs are highly diverse in sequence, with regions of hypervariability confined largely to surfaceexposed loops. Nonsynonymous (replacement) mutations in the regions of the genes coding for these hypervariable loop segments have accumulated at a higher rate than synonymous (silent) mutations. Construction of distance phylograms, based on comparisons of PAG and related aspartic proteinase amino acid sequences, suggests that much diversification of the PAG genes occurred after the divergence of the Artiodactyla and Perissodactyla, but that at least one gene is represented outside the hooved species. The results also suggest that positive selection of duplicated genes has acted to provide considerable functional diversity among the PAGs, whose presence at the interface between the placenta and endometrium and in the maternal circulation indicates involvement in fetal-maternal interactions.

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A complex resistance locus inSolanum americanumrecognizes a conservedPhytophthoraeffector

Witek

Lin

Karki

et al. 2020

Preprint

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1 2 Late blight caused by Phytophthora infestans greatly constrains potato production. 3 Many Resistance (R) genes were cloned from wild Solanum species and/or introduced 4 into potato cultivars by breeding. However, individual R genes have been overcome by 5 P. infestans evolution; durable resistance remains elusive. We positionally cloned a 6 new R gene, Rpi-amr1, from Solanum americanum, that encodes an NRC helper-7 dependent CC-NLR protein. Rpi-amr1 confers resistance in potato to all 19 P. infestans 8 isolates tested. Using association genomics and long-read RenSeq, we defined eight 9 additional Rpi-amr1 alleles from different S. americanum and related species. Despite 10 only ~90% identity between Rpi-amr1 proteins, all confer late blight resistance but 11 differentially recognize Avramr1 orthologs and paralogs. We propose that Rpi-amr1 12 gene family diversity facilitates detection of diverse paralogs and alleles of the 13 recognized effector, enabling broad-spectrum and durable resistance against P. 14 infestans. Pathogen enrichment Sequencing) enable rapid definition of allelic variation 63 and mapping of plant NLRs, or discovery of variation in pathogen effectors 21-23 . 64 Combined with single-molecule real-time (SMRT) sequencing, SMRT RenSeq enabled 65 cloning of Rpi-amr3 from Solanum americanum 24 . Similarly, long read and cDNA 66 PenSeq enabled us to identify Avramr1 from P. infestans 25 . 67 4 68In this study, we further explored the genetic diversity of S. americanum, and by 69 applying sequence capture technologies, we fine-mapped and cloned Rpi-amr1 from S. 70 americanum, (usually) located on the short arm of chromosome 11. Multiple Rpi-amr1 71 homologs were found in different S. americanum accessions and in relatives, including 72Solanum nigrescens and Solanum nigrum. Functional alleles show extensive allelic 73 variation and confer strong, broad-spectrum resistance to all 19 tested diverse P. 74 infestans isolates. Although differential recognition was found between different Rpi-75 amr1 and Avramr1 homologs, all Rpi-amr1 alleles recognize the Avramr1 homologs 76 from Phytophthora parasitica and Phytophthora cactorum. Our study reveals unique 77properties of genetic variation of R genes from "non-host" species. 78 79

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Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution: II. Polycondensations

Cited by 4 publications

References 17 publications

Living strategies of unusual life forms on Earth and the relevance to astrobiology

Living strategies of unusual life forms on Earth and the relevance to astrobiology

The diversity and evolutionary relationships of the pregnancy-associated glycoproteins, an aspartic proteinase subfamily consisting of many trophoblast-expressed genes

A complex resistance locus inSolanum americanumrecognizes a conservedPhytophthoraeffector

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