II. 13. Additional information on telotrisomic analysis with triple marker stock (br, fc, gs3) on the short arm of chromosome 1. (1)
Azizeh Shahla and T. Tsuchiya, Department Agronomy, Colorado State University, Fort Collins, Colorado 80523, U.S.A.
(1) Supported partly by USDA/SEA Competitive Research Grant 5901-0410-9-0334-0 and 82-CRCR-1-1020 and USDA/SEA-CSU Cooperative Research Grant-58-9AHZ-2-265 to T. Tsuchiya.
In previous study (Shahla and Tsuchiya, 1979) the three marker genes, br (brachytic), fc (chlorina) and gs3 (glossy sheath 3) were associated with the short arm of chromosome 1 (1S) by telotrisomic analysis. Because the three genes are very closely linked, the total number of plants studied was not adequate to determine the correct order of the 3 marker genes. The result from conventional linkage analysis (Shahla, 1980) has shown that the gene fc is located in the middle 5.386 and 2.107 map units apart from genes br and gs3, respectively. The following F2 population results add to the previous data (Table 1).
The presence of homozygous recessives in the trisomic portion indicates that the position of all 3 genes are far from the centromere, but it did not show which gene is closer to the centromere. However, in the diploid portion a small number of homozygotes were observed for br gene. Genes fc and gs3 showed the same number of homozygotes due to the very close linkage between them. Therefore, from the data in the diploid portion it may be concluded that br is located in the distal segment on the short arm of chromosome 1 (1S), fc is in the middle and gs3 is the one nearest to the centromere. This result is in agreement with the linkage map of chromosome 1 in barley.
References:
Shahla, A. 1980. Physical localization of genes in the short arm of chromosome 1 (1S) in barley. Ph.D. Thesis, Colorado State University.
Shahla, A. and T. Tsuchiya. 1979. Telotrisomic analysis for three genes (br, fc, gs3) on the short arm of chromosome 1. BGN 9:92-93.
