<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>It is not known when the polyploid coast redwood (<italic>Sequoia sempervirens</italic>) evolved from its diploid ancestors, and what is its type of polyploidy. Whether close relatives of <italic>Sequoia</italic>, giant sequoia (<italic>Sequoiadendron giganteum</italic>) and dawn redwood (<italic>Metasequoia glyptostroboides</italic>), have possibly contributed to the ancestry of hexaploid of <italic>Sequoia</italic> remains an open question. The nature of hexaploidy in <italic>Sequoia</italic> has baffled biologists for more than a century. Based on the chromosome configurations in <italic>Sequoia</italic>, G. Ledyard Stebbins was the first geneticists who postulated in 1948 that <italic>Sequoia</italic> is an autoallohexaploid (AAAABB), and an ancient species of <italic>Metasequoia</italic> might have been one of the putative ancestors of <italic>Sequoia</italic>. After its chromosome number (2n=6x=66) was confirmed in hexaploid <italic>Sequoia</italic>, the type of polyploidy in <italic>Sequoia</italic> has been further investigated for the past 70 years by a number of investigators, using cytogenetic and genetic data. Although an autoallohexaploid (AAAABB) origin of <italic>Sequoia</italic> has remained one of the dominant hypotheses until recently, an alternative hypothesis, amongst other possible origins, was also put forth by Ahuja and Neale (2002), that <italic>Sequoia</italic> may be partially diploidized autohexaploid (AAAAAA), derived from some ancestral species of <italic>Sequoia</italic>, thus carrying a single ancestral genome. Cytogenetic, molecular genetics, and genome sequence data now support the hypothesis that <italic>Sequoia</italic> originated as an autohexaploid.</p>
</abstract>

It is not known when the polyploid coast redwood (Sequoia sempervirens) evolved from its diploid ancestors, and what is its type of polyploidy. Whether close relatives of Sequoia, giant sequoia (Sequoiadendron giganteum) and dawn redwood (Metasequoia glyptostroboides), have possibly contributed to the ancestry of hexaploid of Sequoia remains an open question. The nature of hexaploidy in Sequoia has baffled biologists for more than a century. Based on the chromosome configurations in Sequoia, G. Ledyard Stebbins was the first geneticists who postulated in 1948 that Sequoia is an autoallohexaploid (AAAABB), and an ancient species of Metasequoia might have been one of the putative ancestors of Sequoia. After its chromosome number (2n=6x=66) was confirmed in hexaploid Sequoia, the type of polyploidy in Sequoia has been further investigated for the past 70 years by a number of investigators, using cytogenetic and genetic data. Although an autoallohexaploid (AAAABB) origin of Sequoia has remained one of the dominant hypotheses until recently, an alternative hypothesis, amongst other possible origins, was also put forth by Ahuja and Neale (2002), that Sequoia may be partially diploidized autohexaploid (AAAAAA), derived from some ancestral species of Sequoia, thus carrying a single ancestral genome. Cytogenetic, molecular genetics, and genome sequence data now support the hypothesis that Sequoia originated as an autohexaploid.

Origin and genetic nature of polyploidy in paleoendemic coast redwood (<italic>Sequoia sempervirens</italic> (D. Don) Endl.)

Silvae Genetica

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Origin and genetic nature of polyploidy in paleoendemic coast redwood ( (D. Don) Endl.)

It is not known when the polyploid coast redwood (Sequoia sempervirens) evolved from its diploid ancestors, and what is its type of polyploidy. Whether close...

Origin and genetic nature of polyploidy in paleoendemic coast redwood (Sequoia sempervirens (D. Don) Endl.)

Pubblicato online: 15 ago 2022

Pagine: 54 - 65

DOI: https://doi.org/10.2478/sg-2022-0007

Parole chiave
Coast redwood, Sequoia, Hexaploid, Type of polyploidy, Cytogenetics, Phylogenetics, Molecular genetics, Autohexaploid, Auto-allohexaploid

© 2022 M. Raj Ahuja, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Origin and genetic nature of polyploidy in paleoendemic coast redwood (Sequoia sempervirens (D. Don) Endl.)

Pubblicato online: 15 ago 2022

Pagine: 54 - 65

DOI: https://doi.org/10.2478/sg-2022-0007

Parole chiaveCoast redwood, Sequoia, Hexaploid, Type of polyploidy, Cytogenetics, Phylogenetics, Molecular genetics, Autohexaploid, Auto-allohexaploid

© 2022 M. Raj Ahuja, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Parole chiave
Coast redwood, Sequoia, Hexaploid, Type of polyploidy, Cytogenetics, Phylogenetics, Molecular genetics, Autohexaploid, Auto-allohexaploid