II. 4. Genetic studies with acrotrisomic 5S5L in barley.(1)
A. Shahla and T. Tsuchiya, Department of Agronomy, Colorado State University, Fort Collins, Colorado 80523 U.S.A.
(1) Supported by USDA Competitive Research Grant 82-CRCR-1-1020 and USDA-CSU Cooperative Research Grant 58-9AHZ-2-265.
Six genetic marker genes located on chromosome 5 were tested with acrotrisomic 5S5L. The acrocentric chromosome had a complete short arm (5S) and 40% proximal segment of the long arm (5L) (Shahla and Tsuchiya, 1983). Acrotrisomics as the female parent were crossed with the marker stocks as the male parent. Segregation ratios were observed for acrotrisomics and diploids in the F2 population (Table 1). The genetic ratio is modified for the genes which are located on the extra acrocentric chromosome, but not for the genes in the deficient segment.
Table 1. F2 segregation of crosses between acrotrisomic 5S5L and various marker stocks.
Genes fs2, g, and f3 showed a trisomic ratio with acrotrisomic 5S5L. Disomic ratios were obtained for genes f7, trd, and int-a' with an appreciable number of recessive homozygotes in the trisomic portions indicating that they are located in the missing distal segment of chromosome 5L. This genetic data showed that fs2, g, and f3 are located in the 40% proximal segment of the long arm of chromosome 5. This experiment demonstrated the use of acrotrisomics in physical gene mapping and associating genes with a specific segment of chromosome arm.
Reference:
Shahla, A. and T. Tsuchiya. 1983. Further studies on acrotrisomic for
5S5L. (formerly meta lA) in barley. BGN 13:23-24.
