Biology subjects

Priyam, A.

Publications and source records attributed to Priyam, A..

3 recordsLinked to original sources

bioRxiv2022

No supergene despite social polymorphism in the big-headed ant Pheidole pallidula

Ant colonies ancestrally contained one queen and her non-reproductive workers. This is also the case for many but not all colonies of the Mediterranean big-headed ant Pheidole pallidula. Indeed, this species also has a derived form of social organization with multiple reproductive queens in the colony. The co-existence of two social forms also independently evolved in three other lineages of ants. In each of those lineages, variants of a supergene region of suppressed recombination determine social form. This is likely because supergene regions can link advantageous combinations of alleles from multiple loci. We thus hypothesized that a supergene region also determines colony queen number in the big-headed ant. To test this, we performed extensive population genetic analyses and genomic comparisons. We find no evidence of a supergene-like region with differentiation between single- and multiple-queen colonies. Our results show that a complex social polymorphism can evolve and be maintained without supergenes.

evolutionary biology↗

bioRxiv2021

Parameter exploration improves the accuracy of long-read genome assembly

Long-molecule sequencing is now routinely applied to generate high-quality reference genome assemblies. However, datasets differ in repeat composition, heterozygosity, read lengths and error profiles. The assembly parameters that provide the best results could thus differ across datasets. By integrating four complementary and biologically meaningful metrics, we show that simple fine-tuning of assembly parameters can substantially improve the quality of long-read genome assemblies. In particular, modifying estimates of sequencing error rates improves some metrics more than two-fold. We provide a flexible software, CompareGenomeQualities, that automates comparisons of assembly qualities for researchers wanting a straightforward mechanism for choosing among multiple assemblies.

bioinformatics↗

bioRxiv2021

Recurring adaptive introgression of a supergene that determines social organization

Introgression has been proposed as an essential source of adaptive genetic variation. However, a key barrier to adaptive introgression is that recombination can break down combinations of alleles that underpin many traits. This barrier might be overcome in supergene regions, where suppressed recombination leads to joint inheritance across many loci. Here, we study the evolution of a large supergene region that determines a major social and ecological trait in Solenopsis fire ants: whether colonies have one queen or multiple queens. Using coalescent-based phylogenies built from the genomes of 365 haploid fire ant males, we show that the supergene variant responsible for multiple-queen colonies evolved in one species and repeatedly spread to other species through introgressive hybridization. This finding highlights how supergene architecture can enable a complex adaptive phenotype to recurrently permeate species boundaries.

evolutionary biology↗