Chromosomal assignment of five equine genes responsible for the development of the skeletal and nervous systems

FISH mapping of six genes responsible for development of the nervous and skeletal systems on donkey (Equus asinus) chromosomes

The results obtained in the present study made it possible to place selected markers responsible for development of the nervous and skeletal systems on the physical map of the donkey genome. Fluorescence in situ hybridization (FISH) was used to localize genes such as GDF5 (15q13), FRZB (4q23.1), TWIST (1q31), PAX6 (20q25), SALL1 (24q15) and SHH (1q35) on donkey chromosomes. The identification of their localization confirmed previously proposed homologies using ZOO-FISH technique, except for FRZB and SALL1 genes. This suggests that they were affected by rearrangements that changed their localization compared to horse, and in the case of the SALL1 gene also compared to human.

The horse genome derby: racing from map to whole genome sequence

The map of the horse genome has undergone unprecedented expansion during the past six years. Beginning from a modest collection of approximately 300 mapped markers scattered on the 31 pairs of autosomes and the X chromosome in 2001, today the horse genome is among the best-mapped in domestic animals. Presently, high-resolution linearly ordered gene maps are available for all autosomes as well as the X and the Y chromosome. The approximately 4350 mapped markers distributed over the approximately 2.68 Gbp long equine genome provide on average 1 marker every 620 kb. Among the most remarkable developments in equine genome analysis is the availability of the assembled sequence (EquCab2) of the female horse genome and the generation approximately 1.5 million single nucleotide polymorphisms (SNPs) from diverse breeds. This has triggered the creation of new tools and resources like the 60K SNP-chip and whole genome expression microarrays that hold promise to study the equine genome and transcriptome in ways not previously envisaged. As a result of these developments it is anticipated that, during coming years, the genetics underlying important monogenic traits will be analyzed with improved accuracy and speed. Of larger interest will be the prospects of dissecting the genetic component of various complex/multigenic traits that are of vital significance for equine health and welfare. The number of investigations recently initiated to study a multitude of such traits hold promise for improved diagnostics, prevention and therapeutic approaches for horses.