The genome sequence of the lesser marbled fritillary, Brenthis ino, and evidence for a segregating neo-Z chromosome

The lesser marbled fritillary, Brenthis ino (Rottemburg, 1775), is a species of Palearctic butterfly. Male Brenthis ino individuals have been reported to have between 12 and 14 pairs of chromosomes, a much-reduced chromosome number than is typical in butterflies. Here, we present a chromosome-level genome assembly for Brenthis ino, as well as gene and transposable element annotations. The assembly is 411.8 Mb in length with a contig N50 of 9.6 Mb and a scaffold N50 of 29.5 Mb. We also show evidence that the male individual from which we generated HiC data was heterozygous for a neo-Z chromosome, consistent with inheriting 14 chromosomes from one parent and 13 from the other. This genome assembly will be a valuable resource for studying chromosome evolution in Lepidoptera, as well as for comparative and population genomics more generally.AM is supported by an E4 PhD studentship from the Natural Environment Research Council (NERC, NE/S007407/1). KL is supported by a fellowship from the Natural Environment Research Council (NERC, NE/L011522/1). RV is supported by Grant PID2019-107078GB-I00 funded by Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación (MCIN/AEI/10.13039/501100011033). VD is supported by the Academy of Finland (Academy Research Fellow, decision no. 328895). This work was supported by a European Research Council starting grant (ModelGenomLand 757648) to KL and a David Phillips Fellowship (BB/N020146/1) by the Biotechnology and Biological Sciences Research Council (BBSRC) to AH.Peer reviewe