Nearly Identical Paralogs: Implications for Maize (Zea mays L.) Genome Evolution

摘要: As an ancient segmental tetraploid, the maize (Zea mays L.) genome contains large numbers of paralogs that are expected to have diverged by a minimum 10% over time. Nearly identical (NIPs) defined as paralogous genes exhibit > or = 98% identity. Sequence analyses "gene space" inbred line B73 genome, coupled with wet lab validation, revealed that, conservatively, at least approximately 1% NIP, rate substantially higher than in Arabidopsis. In most instances, both members NIP pairs expressed and therefore potentially functional. Of evolutionary significance, many families also differential expression. The finding some NIPs closely linked genetically while others unlinked is consistent multiple modes origin. provide mechanism for circumvent inherent limitation diploid genomes can carry two "alleles" per "locus." such, may played important roles during evolution domestication contribute success long-term selection experiments this crop species.