scholarly journals The positions of the centromeres in linkage groups II and IX of the mouse

1968 ◽  
Vol 11 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Mary F. Lyon ◽  
Jane M. Butler ◽  
Richard Kemp

In mice heterozygous for translocation T(2;?)163H, and also for linkage group II markers, the cw locus shows close linkage with the point of rearrangement (about 1−2% recombination). Since T 163 was apparently formed by fusion of two chromosomes near their centromeres, this means that the centromere must lie at the cw end of linkage group II. In homozygotes for T(2; 9)138Ca the genes T and d show significant linkage, indicating that their loci are on opposite sides of the trans-location break. Since, from previous data, the break is known to be proximal to d, it must then be distal to T and, again from previous data, the order of loci hi linkage group IX must be centromere-T-tf-T 138 break.

1970 ◽  
Vol 15 (2) ◽  
pp. 227-235 ◽  
Author(s):  
A. G. Searle ◽  
Gillian M. Truslove

SUMMARYMice heterozygous for rump-white (Rw) have white hair in lumbo-sacral and caudal regions, although the tail-tip is sometimes pigmented. The homozygote is lethal in utero. No recombination has been found between Rw and the very closely linked spotting genes patch (Ph) and the viable allele of W (Wv). The compounds between these genes are all viable and fertile, although individual homozygotes are either lethal (Ph, Rw) or sterile and anaemic (Wv). It is concluded that they are non-allelic, but form a gene triplet. Close linkage between a cluster of dominant spotting genes and an angora gene in mouse and rabbit provide evidence for homology of part of linkage group II in the rabbit and part of linkage group XVII in the mouse.


1972 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Anne McVittie

SUMMARYEight newly isolated 9 + 0 mutants each mapped at one of the four previously known loci. Short flagellum mutants were at three loci, two of which (pf7 and pf8) were closely linked; the third, pf21, was unlinked to these two and mapped on linkage group II. The long flagellum mutants lf1 and lf2 were on linkage groups II and XII respectively. Mutants pf8A and lf1 were both recessive to wild-type. There was no evidence for non-Mendelian flagellum mutants.


Genetics ◽  
1979 ◽  
Vol 92 (2) ◽  
pp. 419-435
Author(s):  
Robert K Herman ◽  
James E Madl ◽  
Claire K Kari

ABSTRACT Thirteen chromosomal duplications, all unlinked to their linkage group of origin, have been identified following X-irradiation. Ten are X-chromosome duplications, of which six are half-translocations on three autosomomal linkage groups and four are free fragments. Five of the half-translocations are homozygous fertile and two are recognizable cytologically as chromosome satellites, both of which show some mitotic instability. The free-X duplications show varying tendencies for loss. Three appear not to overlap in extent previously identified free-X duplications. The fourth carries genes from linkage group V, as well as X. Three duplications of a portion of linkage group II were identified and found to be free and quite stable in hyperploids. Some of the free duplications tend to disjoin from the X chromosome in males. New X-chromosome map data are presented.


Genetics ◽  
1993 ◽  
Vol 133 (4) ◽  
pp. 865-874
Author(s):  
J A Holmes ◽  
D E Johnson ◽  
S K Dutcher

Abstract Linkage group XIX (or the UNI linkage group) of Chlamydomonas reinhardtii has been reported to show a circular meiotic recombination map. A circular map predicts the existence of strong chiasma and chromatid interference, which would lead to an excess number of two-strand double crossovers during meiosis. We have tested this prediction in multipoint crosses. Our results are consistent with a linear linkage group that shows positive chiasma interference and no chromatid interference. Chiasma interference occurs both within arms and across the centromere. Of the original loci that contributed to the circular map, we find that two map to other linkage groups and a third cannot be retested because the mutant strain that defined it has been lost. A second reported unusual property for linkage group XIX was the increase in meiotic recombination with increases in temperature during a period that precedes the onset of meiosis. Although we observed changes in recombination frequencies in some intervals on linkage group XIX in crosses to CC-1952, and in strains heterozygous for the mutation ger1 at 16 degrees, we also show that our strains do not exhibit the previously observed patterns of temperature-sensitive recombination for two different pairs of loci on linkage group XIX. We conclude that linkage group XIX has a linear genetic map that is not significantly different from other Chlamydomonas linkage groups.


1966 ◽  
Vol 8 (1) ◽  
pp. 111-113 ◽  
Author(s):  
D. S. Falconer ◽  
J. H. Isaacson

Curly-whiskers (cw) is a recessive gene which was found in 1958 by Mr C. J. W. Smith of the Chester Beatty Research Institute, London. It arose in a subline of the CBA/Cbi inbred strain. The first mutant animals were one male and one female in a litter of five. The two mutants were mated together and a sib-mated subline was continued from them in which 500 mice were bred, all of which were curly-whiskered. This established the mutant to be fully penetrant. Curly-whiskers resembles the hair-waving genes in causing waving of the vibrissae, but it has no obvious waving effect on the hairs of the coat. The coat texture is, however, slightly abnormal and Mr Smith noted also that on the CBA background there was an appreciable darkening of the coat colour. Homozygotes (cw/cw) are easily classifiable soon after birth by the curled vibrissae. Heterozygotes (+/cw) often have slightly curled vibrissae, and the gene is therefore not fully recessive; but the distinction between +/cw and +/+ could not be relied on, and in the linkage tests cw was treated as a recessive gene.


Genome ◽  
1997 ◽  
Vol 40 (4) ◽  
pp. 544-551 ◽  
Author(s):  
Yonghe Bai ◽  
T. E. Michaels ◽  
K. P. Pauls

Seven hundred and fifty-six random primers were screened with bulks of genomic DNA from common bacterial blight (CBB) resistant and susceptible bean plants. The plants were from a breeding population derived from an interspecific cross between Phaseolus acutifolius and Phaseolus vulgaris. Four RAPD markers, named R7313, RE416, RE49, and R4865, were found to be significantly associated with CBB resistance in this population. Forty-nine molecular markers segregating in the population were clustered into 8 linkage groups by a MAPMAKER linkage analysis. The largest linkage group was 140 cM long and contained 25 marker loci, including marker R4865. Markers R7313, RE416, and RE49 were clustered on another linkage group. A regression analysis indicated that the markers in these two groups together accounted for 81% of the variation in CBB resistance in the population. The addition of another marker, M56810, which was not individually associated with CBB resistance, increased the total contribution to the trait to 87%.Key words: Phaseolus vulgaris L., common bacterial blight (CBB), polymerase chain reaction (PCR), RAPD markers, linkage groups.


1984 ◽  
Vol 26 (6) ◽  
pp. 762-764 ◽  
Author(s):  
Peter S. Dawson

Reindeer (Rd) is a dominant mutation affecting antenna morphology in the tenebrionid flour beetle, Tribolium castaneum. In contrast with most dominant mutants previously described for this species, homozygotes are fully viable, thus making Rd very useful for genetic studies. Rd is tentatively assigned to either linkage group IX or X. Abbreviated appendages (aa), formerly placed in linkage group X, is reassigned to linkage group V on the basis of demonstrated linkage to jet (j).Key words: Tribolium, mutation Rd, linkage, antenna morphology.


Helia ◽  
2000 ◽  
Vol 23 (33) ◽  
pp. 65-76
Author(s):  
V.V. Kirichenko ◽  
V.N. Popov

SUMMARY The genetics of anodal esterase (Est), cathodal esterase (cEst), cathodal acid phosphatase (cAcp) and malate dehydrogenase (Mdh) has been studied in mature seeds and leaves (genetics of cAcp and Mdh has not been studied in leaves) of sunflower (Helianthus annuus L.). A total of ten loci (four loci of anodal esterase, two loci of cathodal esterase, three loci of malate dehydrogenase and one locus of cathodal acid phosphatase) have been identified and described. Five esterase loci (Est1, Est2, Est3, Est4, cEst5), three malate dehydrogenase loci and one locus of cathodal acid phosphatase are expressed in seeds. Three esterase loci (Est2, cEst5 and cEst6) are expressed in leaves. The analysis of linkage between these loci has been made. Two linkage groups have been found. The sequence of the loci in the first linkage group was Mdh2-Est1- Est2-Est3-cEst5. In the second linkage group it was Est4-cAcp1. Linkages have been analyzed between three isoenzymatic loci expressed in leaves and between two loci controlling morphological traits (branched stem and male fertility restoration). The linkage between morphological traits and isoenzymatic loci has not been revealed. It has been revealed in Br-Rf pair.


2021 ◽  
Author(s):  
Julie Graham ◽  
Kay Smith ◽  
Katrin MacKenzie ◽  
Linda Milne ◽  
Nikki Jennings ◽  
...  

Abstract Background The changing climate is altering timing of key fruit ripening processes and increasing the occurrence of fruit defects. This work aimed to expand our knowledge of the genetic control of the ripening process in raspberry by examining a biennial x primocane F1 population to determine if the progeny exhibited both primocane and biennial flowering modes, which if any was dominant, and to identify QTL and genome locations associated with fruit development to understand how developmental control in this population differs from a biennial x biennial F1 population previously studied. Results The progeny from this biennial x primocane population exhibited primocane fruiting completing their lifecycle in a single season and also fruiting on second-year wood not removed in season one. QTL associated with rate of fruit development were identified on both primocane and fruiting canes with both parents impacting. Conclusions Novel QTL associated with the developmental process of primocane fruiting were identified. These in the main, differed from developmental QTL for similar developmental stages on fruiting canes (second year canes) with only one significant overlap on linkage group 6. In general, the process of development on fruiting canes overall differed from that in a biennial x biennial population, with the differences being greatest on linkage groups 3 and 6 suggesting control of development differs in the different fruiting types. Further understanding will be achieved by examining genome regions linked to QTL to allow breeding to meet climate requirements for yield stability.


Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1277-1288
Author(s):  
Stephen L Johnson ◽  
Michael A Gates ◽  
Michele Johnson ◽  
William S Talbot ◽  
Sally Horne ◽  
...  

Abstract The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.


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