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

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