1987 Fiscal Year Final Research Report Summary

Cytogenetic study on the chromosome mutation and karyotype differentiation in Haplopappus gracilis (2n=4), an annual Compositae

Research Project

Project/Area Number	60540408
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	遺伝学
Research Institution	Naruto University of Education
Principal Investigator	YONEZAWA Yoshihiko Naruto Univ. of Education, Assoc. Prof., 学校教育学部, 助教授 (90033935)
Project Period (FY)	1985 – 1987
Keywords	Haplopappus gracilis / Interchange / Zygotic lethality / 動原体の非共立移行
Research Abstract	1. A spontaneous interchange was found in a strain of Haplopappus gracilis (2n=4), an annual Compositae. Judging from the distribution of early condensing regions in the interchanged chromosomes, the breakpoints were found to be the interstitial position (between the centromere and early condensing region at intercalary position) of long arm in lg(J) chromosome and the subdistal position of long arm in 2g chromosome. 2. At first metaphase in pllen meiosis of interchange heterozygotes, four types of quadrivalents were observed; ring, chain, cross and 3+1 type. In these the 3+1 type (trivalent+univalent-like) may arise from the 3:1 segregation of chromosomes by noncoorientation of two intermediate centromeres. 3. Up to the present, it has not been possible to obtain interchange homozygotes by inbreeding its heterozygotes. So the zygotic lethality may be induced in the homozygous combination of interchanged chromosomes.

(3 results)