Chapter 7 - Polyploidy in Plants

Abstract

This chapter provides a discussion of recent advancements, in context to plant polyploidy. Polyploidy plays a very important role in plant evolution. Major recent advances in genomic analysis have made it possible to reexamine some of these issues in a new light. Plant polyploidy represents the genetic work of Hugo de Vries on Oenothera lamarckiana mut. Gigas (Onagraceae) that was discovered to be a tetraploid , and from Kuwada's hypothesis regarding an ancient chromosome duplication in maize (Zea mays).Two general types of polyploids have long been recognized: those involving the multiplication of one chromosome set and those resulting from the merger of structurally different chromosome sets. Plant polyploidy is also of substantial importance to humans, given that many of the world's chief agricultural crops have a polyploid origin. Recent genomic studies suggest that even species that were previously assumed to be diploid (small-genomed Arabidopsis thaliana) experienced one or more ancient rounds of genome duplication such as vertebrates, yeast, and other eukaryotic lineages. In this sense, elucidating the causes and consequences of polyploidy appears fundamental to the study of eukaryotic life forms. Whatever the future directions of plant polyploidy research, it is evident that an improved appreciation of the diversity of genetic and higher-level consequences of polyploidy will greatly advance the understanding of the processes that generate, maintain, and alter polyploid lineages in nature—and, by extension, influence the evolution of the global flora as a whole.