Submitted to: Molecular Genetics and Genomics
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/21/2005
Publication Date: 12/16/2005
Citation: Gao, W., Chen, Z.J., Yu, J., Kohel, R.J., Womack, J.E., Stelly, D.M. 2005. Wide-cross whole-genome radiation hybrid mapping of the cotton (Gossypium barbadense L.) genome. Molecular Genetics and Genomics. 275:105-113. Interpretive Summary: This is the second report in use of an alternative mapping approach in cotton. The first one used low dose (5-krad gamma irradiation) on upland cotton (G. hirsutum) and this report used high dose (8-krad gamma irradiation) on sea island cotton (G. barbadense). Assessment of 31 genetic markers on the hybrid panel of 92 cotton plants indicated that 76% of marker retention rate, equivalent to that of a low dose animal radiation hybrid panel. This study complements the first report by offering higher rates of chromosome breakages and more marker retention patterns. It also complements the traditional genetic linkage mapping experiments in cotton.
Technical Abstract: Whole-genome radiation hybrid mapping has been applied extensively to human and certain animal species but little to plants. We recently demonstrated an alternative mapping approach in cotton (Gossypium hirsutum L.) based on segmentation by 5-krad gamma-irradiation and derivation of wild-cross whole-genome radiation hybrids (WWRH). However, limitation observed at the 5-krad level suggested that higher doses might be advantageous. Here, we describe the development of an improved second-generation WWRH panel after higher dose irradiation and compare the resulting map to the 5-krad map. The genome of G. hirsutum (n=26) was used to rescue the radiation-segmented genome of G. barbadense (n=26) introduced via 8- and 12-krad gamma irradiated pollen. Only 8-krad irradiation permitted viable seedlings and construction of a 92-member WWRH mapping panel. Assessment of 31 SSR markers from four chromosomes revealed that 8-krad panel has a marker retention rate of 76%, approximately equivalent to that of loss in a low-dose animal radiation hybrid panel. The resulting maps bolster evidence that WWRH mapping complements traditional linkage mapping and works in cotton, and that the 8-krad panel complements the 5-krad panel by offering higher rates of chromosome breakages, lower marker retention frequency, and more retention patterns.