Challenges of functional genomics applied to farm animal gametes and pre-hatching embryos

The genomes of many commercially important farm animals have already been or are in the process of being decrypted. The genomic era is generating an important wave of downstream developments and derived disciplines are also progressing at a very fast pace. The post-genomic era is already ongoing as exemplified by the introduction of new concepts such as phenomics and functional genomics. These new fields are complementary but do not necessarily target similar applications even though they are often used to refer to one another. In an attempt to categorize the fields according to their respective potential applications, a brief comparative description of phenomics and functional genomics has been put together. However, the focus of this paper is mainly directed toward the introduction of functional genomics specifically applied to the study of the molecular mechanisms underlying gamete and early mammalian developments. Many aspects of the peculiar nature of these cells are introducing numerous methodological challenges to the applicability of functional genomics to unravel their molecular physiology. This is particularly true for transcriptomic studies and it is currently of high relevance for the field of reproductive biology to take into consideration these technical hurdles before tackling the implementation of this technology on a large scale. Nonetheless, functional genomics should prove to be up to the expectations in providing sound information to better understand the fascinating window spanning gamete development that leads to the first weeks of life.