A reference genome for the pea plant provides insight into legume genome evolution

The basic principles of genetics (inheritance and independent segregation) were first discovered and detailed by Gregor Mendel’s meticulous studes of the pea plant in the 1850s and 1860s. Generations of students have learned about dominant and recessive traits — through examples of pea plant height, and pea pod or seed color and shape. The simple laws elucidated by Mendel are experimentally analyzed in classrooms worldwide, and “Mendelian inheritance” is a very common, fundamental term. Although genetic analysis has become orders of magnitude more sophisticated today, Mendel and his pea plant experiments are a great guide and entry point into the study of inheritance.

Most genetics students became familiar with traits of the pea — including green versus yellow and wrinkled versus smooth, often placed within the ordered Punnett square — as their first foray in any course of genetics. Today, a basic understanding of what a genome is, and how it operates, along with a sense of the complexity and sheer amount of information that genomes hold, is important to teach to students — as early in school as possible. When public policy is being shaped around the privacy of individuals’ genetic data, regulation of gene-edited or genetically modified agricultural products, and guidelines for gene-based therapies to treat diseases — it is important for the public to have a basic working knowledge of genetics and genomics.

Furthermore, with increasing interest in the direct-to-consumer genetic testing now used by individuals to find out more about their ancestry — people should understand what those tests are reporting and, more importantly, what their limitations are. This understanding would often require a deeper knowledge of population genetics; however, basic principles, from Mendel to genome sequencing, would aid in interpretation of these genetic testing kits. For example, knowing about the laws of segregation and independent assortment would help people put into context the understanding of family disease risk variants (i.e. how your DNA relates to that of your parents or siblings). Being familiar with concepts of recombination and inheritance would enrich understanding and interpretation of ancestry information. This understanding would also help reduce hype and avoid over-interpretation of genetics findings.

Authors [see attached article & editorial] report the first annotated chromosome-level reference genome assembly for the pea plant.

Phylogenetics (the scientific study of phylogeny, which pertains to the evolutionary history of the relationships of an organism to other organisms according to similarities and differences) and paleogenomics (reconstruction and analysis of genomic information in extinct species, including comparisons of ancient ancestors against modern-day humans) show genomic rearrangements across legumes (e.g. peas, beans, alfalfa, clover, chickpeas, lentils, soybeans, and peanuts) and suggest a major role for repetitive elements in pea genome evolution. Compared to other sequenced Leguminosae genomes, the pea genome shows intense gene dynamics, most likely associated with genome size expansion when the Fabaceae (genus, or tribe, included in the family Leguminosae.) diverged from its sister tribes. During Pisum (genus of the pea) evolution, translocations and transpositions differentially occurred across lineages. This reference sequence will also accelerate our understanding of the molecular basis of agronomically important traits and support crop improvement.


· Nat Genet Sept 2019; 51: 1411–1422 & editorial p. 1297

This entry was posted in Center for Environmental Genetics. Bookmark the permalink.