ANEUPLOIDS FROM NATURAL AND COLCHICINE-INDUCED AUTOTETRAPLOIDS OF SOLANUM

1970 ◽  
Vol 12 (3) ◽  
pp. 601-613 ◽  
Author(s):  
J. G. Th. Hermsen ◽  
M. Wagenvoort ◽  
M. S. Ramanna

Haploids grown from unfertilized egg cells of autotetraploid Solanum (4x = 48) were found to be either euploid (2x = 24) or hyperploid (25 through 28 chromosomes), the proportion of hyperploids being 7.6% for S. tuberosum Group Tuberosum, 1.5% for S. tuberosum Group Andigena and 9.4% for the colchicine-induced autotetraploid S. chacoense. Female transmission of the extra chromosome in eight single trisomics varied from 10.0 to 47.1%. Pachytene analysis was carried out in one clone with 27 chromosomes and in two single trisomic clones from S. chacoense. The three extra chromosomes in the first clone were identified as chromosome 2 (nucleolar chromosome), chromosome 5 and chromosome 9 following the numbering system of Yeh and Peloquin (1965). One single trisomic appeared trisomic for chromosome 5, the other probably for chromosome 7. Association of the chromosomes at MI, AI and AII was studied in eight single, two double and one triple trisomic plants. Two plants showed desynapsis. From the meiotic studies of the synaptic trisomics it was apparent that all arc primary trisomics.

Blood ◽  
1976 ◽  
Vol 48 (5) ◽  
pp. 687-696 ◽  
Author(s):  
L Zech ◽  
C Gahrton ◽  
D Killander ◽  
S Franzen ◽  
U Haglund

Abstract The chromosomes of bone marrow cells from ten patients with polycythemia vera (PV) were identified by Q-, G-, and C-banding techniques. Four of the patients had received no treatment with cytotoxic drugs, while three had received 32P only and the other three, in addition, had received busulfan or busulfan and procarbazine. One 73- yr-old male patient treated with venesection only for 4 yr lacked the Y chromosome and had a deletion of the long arm of chromosome 20 (20q-) in all cells investigated. One of the other three patients who had received no drugs had a chromosome abnormality, but only in 1 of 19 identifiable metaphases. However, the abnormality was the same (+9) as the most common one in treated patients. In the group of treated patients, an extra chromosome 9 (+9) was found in three patients, an extra chromosome 8 (+8) in one, and a deletion of the long arm of one chromosome 20 (20q-) in one patient. Multiple aberrations in addition to the extra chromosome 9 were found in one patient in whom the disease had transformed into acute myeloblastic leukemia. The finding of identical chromosomal aberrations (20q- and +9, respectively) in two patients who had received no drugs and in four patients who had received 32P and busulfan or procarbazine favors the view that these aberrations are specifically associated with the disease and not induced by the drugs. With the exception of the patient with acute myeloblastic leukemia, all other patients are alive 1–11 mo after chromosome analyses and 1–229 mo after diagnosis.


Blood ◽  
1976 ◽  
Vol 48 (5) ◽  
pp. 687-696 ◽  
Author(s):  
L Zech ◽  
C Gahrton ◽  
D Killander ◽  
S Franzen ◽  
U Haglund

The chromosomes of bone marrow cells from ten patients with polycythemia vera (PV) were identified by Q-, G-, and C-banding techniques. Four of the patients had received no treatment with cytotoxic drugs, while three had received 32P only and the other three, in addition, had received busulfan or busulfan and procarbazine. One 73- yr-old male patient treated with venesection only for 4 yr lacked the Y chromosome and had a deletion of the long arm of chromosome 20 (20q-) in all cells investigated. One of the other three patients who had received no drugs had a chromosome abnormality, but only in 1 of 19 identifiable metaphases. However, the abnormality was the same (+9) as the most common one in treated patients. In the group of treated patients, an extra chromosome 9 (+9) was found in three patients, an extra chromosome 8 (+8) in one, and a deletion of the long arm of one chromosome 20 (20q-) in one patient. Multiple aberrations in addition to the extra chromosome 9 were found in one patient in whom the disease had transformed into acute myeloblastic leukemia. The finding of identical chromosomal aberrations (20q- and +9, respectively) in two patients who had received no drugs and in four patients who had received 32P and busulfan or procarbazine favors the view that these aberrations are specifically associated with the disease and not induced by the drugs. With the exception of the patient with acute myeloblastic leukemia, all other patients are alive 1–11 mo after chromosome analyses and 1–229 mo after diagnosis.


Genetics ◽  
1988 ◽  
Vol 118 (4) ◽  
pp. 693-704
Author(s):  
R Gelman ◽  
A Watson ◽  
R Bronson ◽  
E Yunis

Abstract In this longevity analysis of 360 BXD recombinant inbred female mice (20 different strains), 2 strains had very significantly shorter survival and 1 strain had very significantly longer survival than the other 17 strains; 4 other strains had less significant lengthening of survival compared to the other 13 strains in a proportional hazards model of survival. Mean survival on the shortest lived strain was 479 days; on the longest lived strain the mean survival was almost double (904 days). Ranges of survival within strain were very large (averaging 642 days), and strain accounted for only 29% of the variation in survival, showing that there are important environmental and/or special developmental effects on longevity even in this colony housed in a single room. Each strain had been typed for markers of 141 regions on 15 chromosomes; 101 of these markers had distinguishable distributions on the 20 strains. The two shortest lived strains had the same alleles for 63% of the markers. The single region most significantly correlated with survival (marked by P450, Coh, Xmmv-35 on chromosome 7) divided the mice into two groups with survival medians which differed by 153 days (755 days for mice with a B genotype; 602 days for mice with a D genotype). Evaluated individually, 44% of the genetic markers (including some markers on 11 of 15 chromosomes with any markers typed) were found to be significantly correlated with survival (P less than 0.05) although one would only expect 5% of the markers to be significant by chance. While studies of many markers should adjust for the multiple comparisons problem, one interpretation of these crude P values is that any experiment with only one of these "significant" markers typed would be likely to conclude that the marker was a significant predictor of survival. Two types of multiple regression models were used to examine the correlation with survival of groups of genes. When a proportional hazards model for survival was done in terms of genotype regions, a six genetic region model best correlated with survival: that marked by P450, Coh, Xmmv-35 on chromosome 7 (B allele lives longer), Ly-24 on chromosome 2 (B allele lives longer), beta 2M and H-3 on chromosome 2 (D allele lives longer) Lamb-2 on chromosome 1 (D allele lives longer), Ltw-4 on chromosome 1 (B allele lives longer), and the Igh area of chromosome 12 (Igh-Sa4, Igh-Sa2, Igh-Bgl, Igh-Nbp, Igh-Npid, Igh-Gte, Odc-8, and Ox-1; D allele lives longer).(ABSTRACT TRUNCATED AT 400 WORDS)


1976 ◽  
Vol 18 (4) ◽  
pp. 753-761 ◽  
Author(s):  
R. A. Finch ◽  
K. J. Kasha

Meiosis was studied in pollen mother cells and embryo sac mother cells of seven lines of eight-paired barley (Hordeum vulgare L.) in diploids (2n = 16) and their haploids (2n = 8). Translocation 5-7a, whose breakpoints are distal on chromosome 5 and in the satellite of chromosome 7, was found in all lines. The extra fragment chromosome (8) is a normal or translocation form of chromosome 5 deficient for terminal regions. In diploids, the extra chromosome behaves regularly at meiosis except for occasional univalent-formation and can form a symmetric ring bivalent, but it never forms chiasmata with other chromosomes. In haploids, however, it forms a low frequency of chiasmata with chromosome 5 but this frequency is reduced when the terminal region of chromosome 5 pairs homologously with the satellite region of 7. Based on the hypothesis used to explain chromosome pairing behavior, it should be possible to derive and identify additional eight-paired lines that would be useful for breeding.


Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1739-1752 ◽  
Author(s):  
Xavier Montagutelli ◽  
Rowena Turner ◽  
Joseph H Nadeau

Abstract Strong deviation of allele frequencies from Mendelian inheritance favoring Mus spretus-derived alleles has been described previously for X-linked loci in four mouse interspecific crosses. We reanalyzed data for three of these crosses focusing on the location of the gene(s) controlling deviation on the X chromosome and the genetic basis for incomplete deviation. At least two loci control deviation on the X chromosome, one near Xist (the candidate gene controlling X inactivation) and the other more centromerically located. In all three crosses, strong epistasis was found between loci near Xist and marker loci on the central portion of chromosome 2. The mechanism for this deviation from Mendelian expectations is not yet known but it is probably based on lethality of embryos carrying particular combinations of alleles rather than true segregation distortion during oogenesis in F1 hybrid females.


Euphytica ◽  
2021 ◽  
Vol 217 (3) ◽  
Author(s):  
Gareth J. Norton ◽  
Anthony Travis ◽  
Panthita Ruang-areerate ◽  
Graeme W. Nicol ◽  
Ayotunde A. Adeosun ◽  
...  

AbstractIt has been estimated that up to 90% of human exposure to cadmium is through food, and that cadmium within rice grains can be a major contributor to that dietary source. In this study genome wide association mapping was conducted on the Bengal and Assam Aus Panel (BAAP) of rice to identify quantitative trait loci and candidate genes for lowering grain cadmium. Field experiments were conducted over two years under two different irrigation systems: continually flooded and alternate wetting and drying (AWD). There was significant effects of water treatment, genotype, and genotype by water treatment interaction. Importantly, AWD increased grain cadmium, on average, by 49.6% and 108.8% in year 1 and 2 respectively. There was between 4.6 and 28 fold variation in cadmium concentration. A total of 58 QTLs were detected but no loci are clearly specific to one water regime despite approximately 20% of variation attributable to genotype by water regime interaction. A number of QTLs were consistent across most water treatments and years. These included QTLs on chromosome 7 (7.23–7.61, 8.93–9.04, and 29.12–29.14 Mbp), chromosome 5 (8.66–8.72 Mbp), and chromosome 9 (11.46–11.64 Mbp). Further analysis of the loci on chromosome 7 (8.93–9.04 Mbp), identified the candidate gene OsNRAMP1, where cultivars with a deletion upstream of the gene had higher concentrations of cadmium compared to the cultivars that did not have the deletion. The distribution of alleles within the BAAP suggest this QTL is easily detected in this population because it is composed of aus cultivars. Local genome cluster analysis suggest high Cd alleles are uncommon, but should be avoided in breeding.


Genetics ◽  
1975 ◽  
Vol 79 (3) ◽  
pp. 435-450
Author(s):  
P M Nel

ABSTRACT Rhoades (1941) found recombination in the proximal regions of chromosome 5 to be higher in male than in female flowers. Two explanations were proposed to account for the lower female values, namely: (1) there is a basic difference in rates of crossing over in mega- and microsporocytes, or (2) selective orientation of the chromosome 5 bivalent on the meiotic spindle leads to the preferential segregation of noncrossover chromatids to the basal megaspore. These alternatives have been tested by carrying out a half-tetrad analysis of the diploid eggs produced by plants homozygous for the recessive elongate (el) allele. The A2—Bt crossover values determined from the diploid eggs of elongate plants were much lower than those calculated from haploid sperm of both El el and el el plants. Since male and female flowers should have similar cross-over values if the orientation hypothesis were correct, it was concluded that the amount of crossing over in the A2-Bt region of chromosome 5 is intrinsically higher in male than in female meiocytes. In the analysis of diploid eggs the use of the Bt locus, which marks the centric region of chromosome 5, provided information on the origin of diploid eggs. The genotypic constitution of 425 diploid eggs was ascertained. Of these, 20.4% were Bt bt. They could not be accounted for by failure of the second meiotic division or by replication during the interphase between the two meiotic divisions, but are expected if there is a single division with an equational separation of the centromere regions of chromosome 5. The Bt Bt and bt bt genotypes arise from a disjunctional separation. It is proposed that diploid eggs are produced by an abnormal meiosis in which there is one division with either disjunctional or equational separation. Disjunctional separation is more frequent but the ratio of the two types varies from ear to ear. Recombination in the A2-Bt-Pr region of chromosome 5 was found to be higher in the haploid gametes of elongate homozygotes than in El El and El el plants. On the other hand, crossing over was reduced in the Sh-Bz segment of chromosome 9 in elongate plants, but the adjacent Bz—Wx interval was unaffected.


2014 ◽  
Vol 25 (18) ◽  
pp. 2866-2881 ◽  
Author(s):  
Corey L. Smith ◽  
Timothy D. Matheson ◽  
Daniel J. Trombly ◽  
Xiaoming Sun ◽  
Eric Campeau ◽  
...  

Chromatin assembly factor-1 (CAF-1) is a three-subunit protein complex conserved throughout eukaryotes that deposits histones during DNA synthesis. Here we present a novel role for the human p150 subunit in regulating nucleolar macromolecular interactions. Acute depletion of p150 causes redistribution of multiple nucleolar proteins and reduces nucleolar association with several repetitive element–containing loci. Of note, a point mutation in a SUMO-interacting motif (SIM) within p150 abolishes nucleolar associations, whereas PCNA or HP1 interaction sites within p150 are not required for these interactions. In addition, acute depletion of SUMO-2 or the SUMO E2 ligase Ubc9 reduces α-satellite DNA association with nucleoli. The nucleolar functions of p150 are separable from its interactions with the other subunits of the CAF-1 complex because an N-terminal fragment of p150 (p150N) that cannot interact with other CAF-1 subunits is sufficient for maintaining nucleolar chromosome and protein associations. Therefore these data define novel functions for a separable domain of the p150 protein, regulating protein and DNA interactions at the nucleolus.


2020 ◽  
Author(s):  
Catherine Stein ◽  
Penelope Bencheck ◽  
Jacquelaine Bartlett ◽  
Robert P Igo ◽  
Rafal S Sobota ◽  
...  

Background: Tuberculosis (TB) is the most deadly infectious disease globally and highly prevalent in the developing world, especially sub-Saharan Africa. Even though a third of humans are exposed to Myocbacterium tuberculosis (Mtb), most infected immunocompetent individuals do not develop active TB. In contrast, for individuals infected with both TB and the human immunodeficiency virus (HIV), the risk of active disease is 10% or more per year. Previously, we identified in a genome-wide association study a region on chromosome 5 that was associated with resistance to TB. This region included epigenetic marks that could influence gene regulation so we hypothesized that HIV-infected individuals exposed to Mtb, who remain disease free, carry epigenetic changes that strongly protect them from active TB. To test this hypothesis, we conducted a methylome-wide study in HIV-infected, TB-exposed cohorts from Uganda and Tanzania. Results: In 221 HIV-infected adults from Uganda and Tanzania, we identified 3 regions of interest that included markers that were differentially methylated between TB cases and LTBI controls, that also included methylation QTLs and associated SNPs: chromosome 1 (RNF220, p=4x10-5), chromosome 2 (between COPS8 and COL6A3 genes, p=2.7x10-5), and chromosome 5 (CEP72, p=1.3x10-5). These methylation results colocalized with associated SNPs, methylation QTLs, and methylation x SNP interaction effects. These markers were in regions with regulatory markers for cells involved in TB immunity and/or lung. Conclusion: Epigenetic regulation is a potential biologic factor underlying resistance to TB in immunocompromised individuals that can act in conjunction with genetic variants.


2004 ◽  
Vol 24 (9) ◽  
pp. 3588-3595 ◽  
Author(s):  
Kye-Yoon Park ◽  
Elizabeth A. Sellars ◽  
Alexander Grinberg ◽  
Sing-Ping Huang ◽  
Karl Pfeifer

ABSTRACT Igf2 and H19 are coordinately regulated imprinted genes physically linked on the distal end of mouse chromosome 7. Genetic analyses demonstrate that the differentially methylated region (DMR) upstream of the H19 gene is necessary for three distinct functions: transcriptional insulation of the maternal Igf2 allele, transcriptional silencing of paternal H19 allele, and marking of the parental origin of the two chromosomes. To test the sufficiency of the DMR for the third function, we inserted DMR at two heterologous positions in the genome, downstream of H19 and at the alpha-fetoprotein locus on chromosome 5. Our results demonstrate that the DMR alone is sufficient to act as a mark of parental origin. Moreover, this activity is not dependent on germ line differences in DMR methylation. Thus, the DMR can mark its parental origin by a mechanism independent of its own DNA methylation.


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