Comparative genomics shows that viral integrations are abundant and express piRNAs in the arboviral vectors Aedes aegypti and Aedes albopictus

Table 2 Clustering of viral integrations (NIRVS) in piRNA loci of the Ae. aegypti and Ae. albopictus genomes

Host	Genomic region	Length (bp)	% genome	k integrations^a	P-value
Ae. aegypti	piRNA cluster	17,000,000	1.24	54	< 10^-10
	Coding genes	286,538,182	20.82	24	0.66
	Intergenic regions	1,072,461,818	77.94	44	1
Ae. albopictus	piRNA cluster	1,926,670	0.61	9	< 10^-10
	Coding genes	163,407,667	8.26	14	2.08 10^-3
	Intergenic regions	1,803,592,333	91.14	49	1

The probability (P) of observing k NIRVS loci in piRNA clusters, coding genes and intergenic regions. P was estimated using cumulative binomial distribution; a value of P < 0.05 indicates a statistically significant enrichment of NIRVS in the corresponding genomic region
^aSix integrations in the Ae. aegypti genome were in exons of genes within piRNA clusters; in these analyses they were attributed to piRNA clusters. Statistical significance did not change when these integrations were assigned to coding genes (P changed from 0.66 to 0.180)

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