Örjan Carlborg, associate professor at Swedish University of Agricultural Sciences, will give a talk on Wednesday September 10 at Norwegian University of Life Sciences (UMB) campus entitled: Multi-locus epistasis leads to hybrid inferiority in domestic fowl.Time: September 10, 11.15 - 12.00
Place: Håkonshallen, IHA, UMB
Hybrid vigor (heterosis), hybrid inferiority, hybrid breakdown and hybrid incompatibility have all been extensively studied in the past century due to their importance in evolutionary and agricultural genetics. The underlying genetic mechanisms for these phenomena are, however, still largely unknown.
Recently, transgressive segregation (TS) was proposed to describe the proportion of individuals in a hybrid population that have either
higher or lower phenotypes than those of its founder lines. All the classic hybrid phenomena described above can be described based on the magnitude and direction of TS in a studied population.
We have developed a new analytical approach to dissect the genetics of transgressive segregation in segregating hybrid populations. The method facilitates genetic dissection of complex traits in hybrid populations into individual locus effects as well as multi-locus epistasis. Furthermore, we are able to evaluate the functional role of genetic interactions in determining extreme hybrid phenotypes and predict transgressive multi-locus genotypes.
We have used the method to analyze data from two hybrid chicken populations. The populations were selected because the average juvenile bodyweights in hybrids were lower than expected from parental line means and multi-locus epistatic networks had earlier been found to affect these traits. In both populations, we found strong evidence for multi-locus epistasis being the main explanation for the inferior hybrid phenotypes observed. Further use of the method to analyze data from other hybrid populations will give important insights to long-standing questions regarding the functional role of epistasis in determination of e.g. hybrid vigor (heterosis), hybrid breakdown and hybrid incompatibility.
