Community Research and Development Information Service - CORDIS

Damselflies reveal the secret of phenotype variation

Scientists studying one of Europe's most intriguing insects have developed linkage maps to better understand how a species phenotype is linked to its genotype.
Damselflies reveal the secret of phenotype variation
An organism's phenotype is the physical expression of a particular genetic trait. Understanding the genetic basis of phenotype variation is one of the greatest challenges facing biologists. Genetic linkage maps of a species population show the position of known genes relative to each other along a chromosome. As such, they are extremely useful in linking the phenotype to the genetic constitution of an organism, known as the genotype.

Genetic linkage maps are increasingly used by scientists to study the evolution of organisms. They can also be used to identify the genes behind ecologically important traits such as colour polymorphism, and to study the consequences of variations in position of the gene on the chromosome.

Polymorphism, where two or more clearly different phenotypes exist in the same population of a species, was studied in the blue-tailed damselfly (Ischnura elegans) as part of the COLOURFUL GENES initiative. I. elegans exhibits female colour polymorphism with one androchrome, male-mimicking morph and two female-specific morphs. The project constructed the first linkage map for the blue-tailed damselfly and mapped female limited colour polymorphism.

A specific marker was developed to genotype males and larvae in which colour polymorphism is not expressed. In addition, sequences of DNA known as microsatellites and the linkage map were used to study the importance of the movement of genes (known as gene flow) in the I. elegans population in maintaining this polymorphism in blue-tailed damselfly populations.

Several specific microsatellites were developed, tested and used to develop the first linkage map for odonates, the scientific order of carnivorous insects that includes dragonflies and damselflies. The microsatellite study was also used to investigate hybridisation between I. elegans and its sister species in southern Europe. Large numbers of individuals were genotyped with a large number of additional markers using restriction site-associated DNA (RAD) sequencing.

A genome-wide association study (GWAS) was conducted to examine genetic variants between different groups of individuals, where each group corresponded to one of the three female colour morphs. Single-nucleotide polymorphism (SNP) analyses were carried out as well as comparative genome analyses to study gene flow among the natural population. A paper on comparative genome analysis is ready for publication and several other papers have already been published in a renowned scientific journal.

The COLOURFUL GENES project combined cutting-edge molecular technology and ecological research to make a significant contribution to enhancing the EU's scientific excellence in the fields of molecular genetics and evolutionary biology.

Related information

Follow us on: RSS Facebook Twitter YouTube Managed by the EU Publications Office Top