Insights into the domestication of avocado and potential genetic contributors to heterodichogamy

O_LIThe domestication history of avocado (Persea americana) remains unclear, in part due to a lack of suitable genomic tools. C_LIO_LIWe created a reference genome from the Gwen varietal, which is closely related to the economically dominant Hass varietal. We also compiled a database of 34 resequenced accessions that represented the three botanical races of P. americana. C_LIO_LIOur genome assembly had an N50 of 3.37 megabases, a BUSCO score of 91% and was scaffolded with a genetic map, producing 12 pseudo-chromosomes with 49,450 genes. We used the Gwen genome as a reference to investigate the population genomics of avocado. Our analyses were consistent with three separate domestication events; we estimated that the Mexican race diverged from the Lowland (formerly known as West Indian) and Guatemalan races >1 million years ago. We also identified putative targets of selective sweeps in domestication events; within the Guatemalan race, putative candidate genes were enriched for fruit development and ripening. We also investigated divergence between heterodichogamous flowering types. C_LIO_LIWith the help of a new reference genome, we inferred the domestication history of avocado and identified genes that may contribute to heterodichogamy, including genes with functions in pollination and floral development. C_LI