Transcriptional profiles associated with Context dependent behavior in Rock X Sand F1 in Lake Malawi Cichlids

We sought to evaluate the brain gene expression profiles of male courtship display. To assess male display and courtship behavior, we designed a courtship preference assay. We evaluated social interactions between males and females using a 40 gallon tank design with a 'rock' habitat at one end and 'sand' at the other, separated by glass bottom. When parental rock species (Petrotilapia nigra (TaxId 526958), Maylandia zebra (TaxId 106582), Labeotropheus feulliborni) are placed in this tank paradigm, males court females over the rocks. Males of sand species (Mchenga conophorus, Aulonocara baenschi (TaxId 143496), Tramitichromis intermedius (TaxId 323801)) court females over sand and construct species appropriate bowers. When single rock x sand F1 males were placed in this set up with F1 females, males invariably courted females over the 'rock' habitat, suggesting genetic dominance. When two rock x sand F1 males were allowed to compete for F1 females in this tank paradigm, something interesting happened. One male, typically the larger, courted females over the rock habitat, and the other simultaneously constructed bowers to court females in the sand. We detected no difference in GSI (gonadal somatic index) between F1 males behaving as 'socially rock' vs. 'socially sand.' This observation of divergent behavior among interacting F1 brothers suggests an interaction between the genome and the social environment in these males. Overall design: Whole brains of F1 males tested singly (n=2 lone) as well as F1 brothers assayed in dyads (n=4 dyads) were dissected after sacrifice during courtship and interrogated using RNA-seq. Individuals from the same cross are from the same brood/clutch of hybrid progeny i.e. are siblings. Please note that the dyads are brothers and the 'LONE' samples are the F1 males tested singly. Sub and Dom were internal naming conventions, behavioral context is the key distinction between the individuals (whether they perform sand like or rock like behavior); SUB if the individual was behaving on sand, DOM if the individual was behaving on rock and LONE if it was tested singly.