X-RAY INDUCED PERICENTRIC INVERSIONS IN ANOPHELES ALBIMANUS

1977 ◽  
Vol 19 (1) ◽  
pp. 67-74 ◽  
Author(s):  
M. G. Rabbani ◽  
J. A. Seawright ◽  
J. B. Kitzmiller

Sixteen different pericentric inversions, ten on chromosome 2 and six on chromosome 3, have been isolated and characterized. The partial sterility in the inversion heterozygotes ranged from about 28 to 50%. Contrary to theoretical considerations, a curvilinear relationship exists between inversion length and partial sterility, whereby a reduction in sterility was noted for progressively longer inversions. The break-points are distributed randomly over the autosomes, but are observed more frequently in the areas of the salivary gland chromosomes where diffuse and broken bands of variable stainability are located.

1981 ◽  
Vol 23 (1) ◽  
pp. 57-64 ◽  
Author(s):  
S. G. Suguna ◽  
J. A. Seawright ◽  
D. J. Joslyn ◽  
M. G. Rabbani

Two radiation-induced pericentric inversions on chromosome 3 in Anopheles albimanus Wiedemann have been established in homozygous stocks. In(3)17 and In(3)22 cover about 82% and 42%, respectively, of chromosome 3 and should be very useful as crossover suppressors in genetic crosses. In addition, three double-heterozygote stocks were established by combining inversions that had similar breakpoints but were viable only as heterozygotes. These balanced-lethal double heterozygotes can serve as a source of inversion gametes for use in experimental crosses and can be used in surveying populations for lethal chromosomes. Assays of the partial sterility inherent in males heterozygous for a pericentric inversion and a male-linked translocation indicated that the combination of inversions and translocations could be used in genetic control schemes.


1976 ◽  
Vol 6 (4) ◽  
pp. 473-481 ◽  
Author(s):  
R. D. Kreutzer ◽  
J. B. Kitzmiller ◽  
M. G. Rabbani

Abstract Salivary gland chromosome slides of Anopheles albitarsis from Brasil, Colombia and Venezuela indicate that at least three chromosomally differentiated populations of this species exist in this area. The B1 population from Brasil contains one heterozygous inversion in the X and two in the autosomes. Population B2, sympatric with B1 in Brasil, differs from it by two inversions in the X and ten in the autosomes. Population C in Colombia and Venezuela is closer to B1, from which it differs by three inversions in chromosome 2 and three in chromosome 3. Each population, B1, B2 and C may be distinguished with about 98% certainty using the banding patterns of the X chromosomes. Most of the remaining individuals may be identified using a combination of the X and autosomal paracentric inversions. The scarcity of shared inversions argues for little if any natural hybridization among these populations. A standard salivary gland chromosome map, based on the B1 populations, is presented.


1984 ◽  
Vol 26 (5) ◽  
pp. 590-594 ◽  
Author(s):  
S. Narang ◽  
J. A. Seawright ◽  
N. L. Willis

The inheritance and linkage group assignments were determined for the two enzyme loci, glutamate oxaloacetate transaminase (Got-I) and alcohol dehydrogenase (Adh-I). of Anopheles albimanus Weidemann. Got-I was assigned to the proximal position on the genetic map of the right arm of chromosome 2, and Adh-I was mapped at the distal position on the map of the right arm of chromosome 3. Gene sequences and linkage estimates are now available for 23 mutant and enzyme loci in A. albimanus.Key words: glutamate oxaloacetate transaminase, alcohol dehydrogenase, isozyme, Anopheles albimanus, genetic map.


Author(s):  
M.E. Cantino ◽  
M.K. Goddard ◽  
L.E. Wilkinson ◽  
D.E. Johnson

Quantification in biological x-ray microanalysis depends on accurate evaluation of mass loss. Although several studies have addressed the problem of electron beam induced mass loss from organic samples (eg., 1,2). uncertainty persists as to the dose dependence, the extent of loss, the elemental constituents affected, and the variation in loss for different materials and tissues. in the work described here, we used x-ray counting rate changes to measure mass loss in albumin (used as a quantification standard), salivary gland, and muscle.In order to measure mass loss at low doses (10-4 coul/cm2 ) large samples were needed. While freeze-dried salivary gland sections of the required dimensions were available, muscle sections of this size were difficult to obtain. To simulate large muscle sections, frog or rat muscle homogenate was injected between formvar films which were then stretched over slot grids and freeze-dried. Albumin samples were prepared by a similar procedure. using a solution of bovine serum albumin in water. Samples were irradiated in the STEM mode of a JEOL 100C.


1976 ◽  
Vol 31 (6) ◽  
pp. 737-748 ◽  
Author(s):  
Karl-Heinz Tytko

Possible structures and the pertinent reaction pathways for the polymetalate ion present in a slightly soluble polymetalate having the analytical formula A2O · 2 MOs have been derived on the basis of theoretical considerations. Structure and kind of combination of the tetrameric units of one of the possibilities are in agreement with the results of X-ray structure analyses. First the previously proposed planar tetrametalate ion [M4O12(OH)4]4--is formed by stepwise aggregation according to an addition mechanism. This species undergoes a rearrangement of the coordination sphere of two of the M atoms and is then subject to a polycondensation resulting in a polytetrametalate chain, [M4O144-]n.


Author(s):  
Quanya Tan ◽  
Chengshu Wang ◽  
Xin Luan ◽  
Lingjie Zheng ◽  
Yuerong Ni ◽  
...  

Abstract Key message Through substitution mapping strategy, two pairs of closely linked QTLs controlling stigma exsertion rate were dissected from chromosomes 2 and 3 and the four QTLs were fine mapped. Abstract Stigma exsertion rate (SER) is an important trait affecting the outcrossing ability of male sterility lines in hybrid rice. This complex trait was controlled by multiple QTLs and affected by environment condition. Here, we dissected, respectively, two pairs of tightly linked QTLs for SER on chromosomes 2 and 3 by substitution mapping. On chromosome 2, two linkage QTLs, qSER-2a and qSER-2b, were located in the region of 1288.0 kb, and were, respectively, delimited to the intervals of 234.9 kb and 214.3 kb. On chromosome 3, two QTLs, qSER-3a and qSER-3b, were detected in the region of 3575.5 kb and were narrowed down to 319.1 kb and 637.3 kb, respectively. The additive effects of four QTLs ranged from 7.9 to 9.0%. The epistatic effect produced by the interaction of qSER-2a and qSER-2b was much greater than that of qSER-3a and qSER-3b. The open reading frames were identified within the maximum intervals of qSER-2a, qSER-2b and qSER-3a, respectively. These results revealed that there are potential QTL clusters for SER in the two regions of chromosome 2 and chromosome 3. Fine mapping of the QTLs laid a foundation for cloning of the genes of SER.


Genetics ◽  
2001 ◽  
Vol 157 (1) ◽  
pp. 379-387 ◽  
Author(s):  
Naoya Shikazono ◽  
Atsushi Tanaka ◽  
Hiroshi Watanabe ◽  
Shigemitsu Tano

Abstract To elucidate the nature of structural alterations in plants, three carbon ion-induced mutations in Arabidopsis thaliana, gl1-3, tt4(C1), and ttg1-21, were analyzed. The gl1-3 mutation was found to be generated by an inversion of a fragment that contained GL1 and Atpk7 loci on chromosome 3. The size of the inverted fragment was a few hundred kilobase pairs. The inversion was found to accompany an insertion of a 107-bp fragment derived from chromosome 2. The tt4(C1) mutation was also found to be due to an inversion. The size of the intervening region between the breakpoints was also estimated to be a few hundred kilobase pairs. In the case of ttg1-21, it was found that a break occurred at the TTG1 locus on chromosome 5, and reciprocal translocation took place between it and chromosome 3. From the sequences flanking the breakpoints, the DNA strand breaks induced by carbon ions were found to be rejoined using, if present, only short homologous sequences. Small deletions were also observed around the breakpoints. These results suggest that the nonhomologous end-joining (NHEJ) pathway operates after plant cells are exposed to ion particles.


1987 ◽  
Vol 101 (11) ◽  
pp. 1175-1181 ◽  
Author(s):  
Jae Y. Ro ◽  
Bruce Mackay ◽  
John G. Batsakis ◽  
Joiner Cartwright

AbstractThe ultrastructural, X-ray microanalytical, histochemical and immunocytochemi-cal features of intraluminal crystalloids found in adenocarcinomas of the parotid gland have been studied. The crystalloids, putatively derived from an abnormal crystalization of salivary duct proteins, are considerably different from the crystalloids found in normal parotid glands, pleomorphic adenomas, and sialocysts.


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