Arabidopsis thaliana has been the principal model plant for molecular developmental studies of flowers for two decades.
Although several of these insects are amenable to laboratory culture and a variety of experimental manipulations, molecular developmental studies are scarce, and gene discovery rates remain low.
Elongation of anal fins in the southern population of the Japanese medaka is mainly caused by an increase in the number of segments (Kawajiri and Yamahira 2011); therefore, further molecular developmental studies would also help to identify the causative genes.
Among the 15 genes, five are grouped into three classes (A-type, B-type, and C- type), whose combinations have been shown - through molecular developmental genetic studies - to be necessary for floral organ cell specification.
With genomic and transcriptomic sequences available, A. carolinensis is also emerging as an important model organism for cellular, molecular, developmental and regenerative studies.
Establishing a dense map of genetic variations in C. intestinalis is necessary not only for linkage analysis, but also for other experimental biology including molecular developmental and evolutionary studies, because animals from natural populations are typically used for experiments.
Expressed sequence tags (EST) are particularly useful genomic resources because they enable multiple lines of research and can be generated for any organism: ESTs allow the identification of molecular probes for developmental studies, provide clones for DNA microchip construction, reveal candidate genes for mutant phenotypes, and facilitate studies of genome structure and evolution.
These properties make echinoderms an excellent model to study molecular developmental mechanisms and address aspects in evolution of organogenesis.
Based on molecular phylogenies, fossils and detailed developmental studies, the last common ancestor of hemichordates and echinoderms is predicted to have been bilaterally symmetrical, a filter feeder with a paired water vascular system constructed from right and left hydrocoels, and with a muscular post-anal stalk ([43] see references herein).
The three-spined stickleback (Gasterosteus aculeatus) has become a vertebrate 'supermodel' allowing a combination of studies at molecular, developmental, phenotypic, and population genetic levels to explore factors and processes relevant for adaptive evolution in ecologically relevant contexts [ 3, 4].
In recent years, great strides have been made in molecular developmental genetics, which has renewed hopes of integrating the study of embryological development with evolutionary theory; hence the emerging new discipline of 'evolutionary developmental biology', or evo-devo.
