Description:
<jats:title>Significance</jats:title>
<jats:p>Advancements in long-read DNA sequencing technologies provide more comprehensive views of genomes. We used long-read sequences to assemble a Great Dane dog genome that provides several improvements over the existing reference derived from a Boxer. Assembly comparisons revealed that gaps in the Boxer assembly often occur at the beginning of protein-coding genes and have a high-GC content, which likely reflects limitations of previous technologies in resolving GC-rich sequences. Dimorphic LINE-1 and SINEC retrotransposons represent the predominant differences between the Great Dane and Boxer assemblies. Proof-of-principle experiments demonstrated that expression of a canine LINE-1 could promote the retrotransposition of itself and a SINEC_Cf consensus sequence in cultured human cells. Thus, ongoing retrotransposon activity is a major contributor to canine genetic diversity.</jats:p>