THE ORIGIN OF THE ALLOTETRAPLOID <i>CLARKIA GRACILIS</i>

Abdel-Hameed, Fathi; Snow, Richard

doi:10.1111/j.1558-5646.1972.tb00175.x

Cited by 10 publications

(10 citation statements)

References 7 publications

(7 reference statements)

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“…Regarding the second progenitor of C. gracilis, sequence evidence firmly places it in the same subsection as the first, whereas previous evidence from morphology (Lewis and Lewis 1955) and cytogenetics (Abdel-Hameed and Snow 1972) had suggested that the tetraploid arose following hybridization between species from the two subsections. It is quite unlikely that the donor of PgiC1RB belonged to the C. arcuata/C.…”

Section: Discussionmentioning

confidence: 75%

“…The two basal clades coincide with the two taxonomically defined diploid subsections, but new information is provided concerning the origin of the tetraploid. Cytogenetic evidence (Hakansson 1942;Snow 1963;Abdel-Hameed and Snow 1972) indicated that one parent of C. gracilis was C. amoena and further showed that the standard chromosome arrangement of the amoena subgenome of C. gracilis is common to all five subspecies of C. amoena. (Both species have other arrangements as well.)…”

Section: Discussionmentioning

confidence: 99%

“…2) and demonstrates the value of such cytogenetic evidence, when it can be obtained. Abdel-Hameed and Snow (1972) believed the most widespread subspecies, huntiana, was the actual parent of C. gracilis on geographical, morphological, and ecological grounds. Testing this would require sequence evidence from all subspecies, including multiple alleles from each to test for incomplete lineage sorting in these apparently recently derived taxa.…”

Section: Discussionmentioning

confidence: 99%

“…Cytogenetic analysis (Hakansson 1942;Abdel-Hameed and Snow 1972) showed that C. amoena contributed one genome because the experimentally synthesized triploid hybrid showed regular bivalent chromosome pairing between the seven C. amoena chromosomes and the recognizably similar set of chromosomes from C. gracilis. In similar cytogenetic studies, triploid hybrids between C. gracilis and C. arcuata and C. lassenensis showed poor chromosome pairing and rarely as many as five bivalents, leading to the conclusion that the second parent was neither of those diploids, but perhaps an extinct relative of theirs (Hakanssen 1946;Abdel-Hameed and Snow 1972). Electrophoretic studies of isozyme variation in the five diploid species and C. gracilis were consistent with the cytogenetic results (Holsinger and Gottlieb 1988).…”

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confidence: 99%

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MOLECULAR CHARACTERIZATION OF PgiC IN A TETRAPLOID PLANT AND ITS DIPLOID RELATIVES

Ford

Gottlieb

1999

Evolution

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Allotetraploid plant species combine the genomes of related diploid species, but little is known about whether homologous genes from the diploid genomes are expressed, how they interact, or whether they evolve differently when in a common tetraploid nucleus. Polyploidy may lead to gene silencing, but few molecular characterizations of silenced genes encoding enzymes in polyploids and related diploids have been reported. Here we describe the PgiC genes in the tetraploid Clarkia gracilis and related diploid species, which are native from California to southern Washington. PgiC encodes the cytosolic isozyme of phosphoglucose isomerase (PGIC; EC 5.3.1.9). The gene was duplicated in the basal stock of Clarkia and now both genes, PgiC1 and PgiC2, are active in about half of the diploid species, whereas only PgiC1 is active in the others. Clarkia gracilis was found to have three PgiC genes: two PgiC1s and a PgiC2. Reverse-transcriptase-polymerase chain reaction (RT-PCR) experiments, starting with mRNAs prepared from seedling leaves of C. gracilis, showed that the three genes are expressed. Analysis of their sequences showed they are evolving at similar rates to their homologues and that they have the same intron-exon structure. The presence of an expressed PgiC2 in C. gracilis was unexpected because all related diploid species, including one identified as a parent, have only active PgiC1s. The donor of the PgiC2 is now presumed extinct, but parsimony analysis identified its phylogenetic position. None of the PgiC genes that were active when C. gracilis arose were silenced. A possible example of gene conversion involving a 300-nuclectide region of one PgiC1 and PgiC2 was identified, but it probably occurred in the diploid parental species rather than in C. gracilis. PgiC2 is the first known example of an active locus in a tetraploid plant species that is no longer expressed in its diploid relatives.

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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MOLECULAR CHARACTERIZATION OF PgiC IN A TETRAPLOID PLANT AND ITS DIPLOID RELATIVES

Ford

Gottlieb

1999

Evolution

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“…This species is believed to be an allotetraploid that was formed by a cross between the central‐spotted C. amoena and an extinct relative of the basal‐spotted C. lassenensis and C. arcuata (Fig. b) (Abdel‐Hameed & Snow, ). Previous work established that the different spot positions in different subspecies are determined by different alleles at the P locus (Gottlieb & Ford, ).…”

Section: Resultsmentioning

confidence: 99%

How petals change their spots: cis‐regulatory re‐wiring in Clarkia (Onagraceae)

2016

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A long-standing question in evolutionary developmental biology is how new traits evolve. Although most floral pigmentation studies have focused on how pigment intensity and composition diversify, few, if any, have explored how a pattern element can shift position. In the present study, we examine the genetic changes underlying shifts in the position of petal spots in Clarkia. Comparative transcriptome analyses were used to identify potential candidate genes responsible for spot formation. Co-segregation analyses in F individuals segregating for different spot positions, quantitative PCR, and pyrosequencing, were used to confirm the role of the candidate gene in determining spot position. Transient expression assays were used to identify the expression domain of different alleles. An R2R3Myb transcription factor (CgMyb1) activated spot formation, and different alleles of CgMyb1 were expressed in different domains, leading to spot formation in different petal locations. Reporter assays revealed that promoters from different alleles determine different locations of expression. The evolutionary shift in spot position is due to one or more cis-regulatory changes in the promoter of CgMyb1, indicating that shifts in pattern element position can be caused by changes in a single gene, and that cis-regulatory rewiring can be used to alter the relative position of an existing character.

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Origin of Polyploidy

Dar

Rehman

2017

Polyploidy: Recent Trends and Future Perspectives

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THE ORIGIN OF THE ALLOTETRAPLOID CLARKIA GRACILIS

Cited by 10 publications

References 7 publications

MOLECULAR CHARACTERIZATION OF PgiC IN A TETRAPLOID PLANT AND ITS DIPLOID RELATIVES

MOLECULAR CHARACTERIZATION OF PgiC IN A TETRAPLOID PLANT AND ITS DIPLOID RELATIVES

How petals change their spots: cis‐regulatory re‐wiring in Clarkia (Onagraceae)

Origin of Polyploidy

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