BMC Genomics Methodology article A new procedure for determining the genetic basis of a physiological process in a non-model species, illustrated by cold induced angiogenesis in the carp John MJ Herbert1, Francesca M Buffa2, Henrik Vorschmitt1, Stuart Egginton3 and Roy Bicknell*1 BioMed Central Open Access Address: 1Cancer Research UK Angiogenesis Group, Institute for Biomedical Research, Schools of Immunity and Infection and Cancer studies, College of Medicine and Dentistry, University of Birmingham, Birmingham, B15 2TT, UK, 2Cancer Research UK, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DS, UK and 3Division of Medical Sciences, Medical School, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK Email: John MJ Herbert - j.m.herbert@bham.ac.uk; Francesca M Buffa - Francesca.Buffa@imm.ox.ac.uk; Henrik Vorschmitt - h.vorschmitt@bham.ac.uk; Stuart Egginton - s.egginton@bham.ac.uk; Roy Bicknell* - r.bicknell@bham.ac.uk * Corresponding author Published: 23 October 2009 BMC Genomics 2009, 10:490 doi:10.1186/1471-2164-10-490 This article is available from: http://www.biomedcentral.com/1471-2164/10/490 Received: 5 May 2009 Accepted: 23 October 2009 © 2009 Herbert et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Physiological processes occur in many species for which there is yet no sequenced genome and for which we would like to identify the genetic basis. For example, some species increase their vascular network to minimise the effects of reduced oxygen diffusion and increased blood viscosity associated with low temperatures. Since many angiogenic and endothelial genes have been discovered in man, functional homolog relationships between carp, zebrafish and human were used to predict the genetic basis of cold-induced angiogenesis in Cyprinus Carpio (carp). In this work, carp sequences were collected and built into contigs. Human-carp functional homolog relationships were derived via zebrafish using a new Conditional Stepped Reciprocal Best Hit (CSRBH) protocol. Data sources including publications, Gene Ontology and cDNA libraries were then used to predict the identity of known or potential angiogenic genes. Finally, re-analyses of cold carp microarray data identified carp genes up-regulated in response to low temperatures in heart and muscle. Results: The CSRBH approach outperformed all other methods and attained 8,726 carp to human functional homolog relationships for 16,650 contiguous sequences. This represented 3,762 non- redundant genes and 908 of them were predicted to have a role in angiogenesis. The total number of up-regulated differentially expressed genes was 698 and 171 of them were putatively angiogenic. Of these, 5 genes representing the functional homologs NCL, RHOA, MMP9, GRN and MAPK1 are angiogenesis-related genes expressed in response to low temperature. Conclusion: We show that CSRBH functional homologs relationships and re-analyses of gene expression data can be combined in a non-model species to predict genes of biological interest before a genome sequence is fully available. Programs to run these analyses locally are available from http://www.cbrg.ox.ac.uk/~jherbert/. Page 1 of 17 (page number not for citation purposes)