Cytogenetic and Genome Research

Klinger, H.P.

doi: 10.1159/000132111pmid: N/A

Kaelbling, M.; Fechheimer, N.S.

doi: 10.1159/000132112pmid: 4006522

Electron microscopy of synaptonemal complexes in three Gallus domesticus cockerels that were heterokaryotypic for a pericentric inversion in chromosome 2 revealed a low incidence of homologous pairing and a high incidence of nonhomologous pairing. The significance of these results are related to the finding that heterokaryotypic parents have fertility rates that are normal or above normal and produce only balanced gametes. One cockerel apparently had both normal cells and cells with a heteromorphic bivalent 2 in its germ line.

Martin-DeLeon, P.A.; Wolf, S.F.; Persico, G.; Toniolo, D.; Martini, G.; Migeon, B.R.

doi: 10.1159/000132113pmid: 4006523

By hybridizing a tritiated human genomic probe (pGD3) to metaphase chromosomes in situ, we have localized the gene for glucose-6-phosphate dehydrogenase (G6PD) in both the human and mouse complement. The locus on the intact human X chromosome is close to the telomere on the long arm, confirming the assignment based on studies of an X/autosome translocation in human-mouse hybrids. Although the signal:background ratio was reduced for the heterologous hybridization of the human probe to mouse metaphases, 20% of the grains were on the X chromosome and 93% of these were in the A region, relatively close to the centromere. The location of G6PD in mouse and man reflects intrachromosomal transposition of these homologous X loci. Genomic DNAs from mouse and man and from hybrids with human X/autosome translocations were digested with several restriction enzymes including EcoRl, PstI, and HpaII, and Southern blots were probed with ³²P-pGD3. The results of the analysis also confirm the human G6PD assignment and are consistent with a single copy of the locus in the haploid genome of both species.

Takanari, H.; Nakakuki, K.; Izutsu, K.

doi: 10.1159/000132114pmid: 4006524

Out-of-phase DNA synthesis, which is demonstrated cytogenetically as premature chromosome condensation (PCC), was analyzed in endoreduplicated Chinese hamster ovary (CHO) cells induced by colchicine or vincristine. Like conventional polyploid cells, endoreduplicated cells exhibited PCC in either S or G₂. The former was more frequently observed in drug-treated cultures. In addition to these two types of PCC, other mitotic figures showing out-of-phase DNA synthesis were found. Such cells contained both conventional chromosomes (monochromosomes) and diplochromosomes. Differential FPG staining of chromatids in these cells showed that diplochromosomes incorporated BrdU twice while monochromosomes did so once, indicating the occurrence of partial endoreduplication in one of the sister nuclei of multinucleate cells. The possible mechanisms underlying induction of out-of-phase DNA synthesis and production of partial endoreduplication are discussed.

Péquignot, Viegas; Koiffmann, C.P.; Dutrillaux, B.

doi: 10.1159/000132115pmid: 4006525

Based on a comparison of the karyotypes of two Plathyrrhini species, Cacajao melanocephalus (Pitheciinae) and Brachyteles arachnoides (Atelinae), with those of two previously studied species, Lagothrix lagothrica (Atelinae) and C calvus rubicundus (Pitheciinae), it appears that the two Cacajao species have undergone the same number of chromosome rearrangements since they diverged from their common ancestor and that the karyotype of Brachyteles is ancestral to that of Lagothrix. The chromosomal phylogeny of these four species is proposed. A Y-autosome translocation is present in the karyotypes of the two Cacajao species.

Wulf, H.C.; Niebuhr, E.

doi: 10.1159/000132116pmid: 4040003

To explore the influence of sex on sister chromatid exchange (SCE) level, a pair of chimeric twins was examined for differences in SCE frequency between the XX and XY cells present in each individual. By this method, the influence of possible differences in environmental exposure was eliminated. SCE levels were varied by growing the cells in media containing 0, 1.3 × 10^–7, or 6.5 × 10^–7 M melphalan. XX cells showed a higher SCE count than XY cells. This difference increased with increasing SCE level and ranged from 5.4% to 7.8% (P = 0.0003) of the SCE counts. Only about 2% of the difference could be explained by the higher amount of DNA present in the XX cells than in the XY cells. In this case XX cells seemed to be more sensitive to SCE-inducing agents than XY cells.

Lieberman, H.B.; Rabin, M.; Barker, P.E.; Ruddle, F.H.; Varshney, U.; Gedamu, L.

doi: 10.1159/000132117pmid: 2988861

Metallothionein (MT) genes comprise a multigene family encoding low-molecular-weight, heavy-metal-binding proteins. We have mapped a human MT-II processed gene to chromosome 4, using Southern blotting in combination with a human × mouse hybrid clone panel containing defined subsets of human chromosomes. We have further localized this gene to region p11→q21, using in situ hybridization.

Simon, D.; Searls, D.B.; Cao, Y.; Sun, K.; Knowles, B.B.

doi: 10.1159/000132118pmid: 2988862

The single site of integration of hepatitis B virus in the human hepatocellular carcinoma cell line Hep 3B 2-1/7 was found to segregate with human chromosome 12 in somatic cell hybrids. Analysis of metaphase spreads of Hep 3B 2-1/7 following in situ hybridization with pHBV revealed integration at 12q13→q14, a location that coincides with a fragile site, fra (12q13). The possible significance of this location to the development of hepatocellular carcinomas is discussed.

Quirk, S.; Chou, W.-G.; Polakowska, R.; Zain, S.B.; Young, F.E.; Doherty, R.A.

doi: 10.1159/000132119pmid: 3839179

The location of the human antihemophilic Factor IX has been more specifically assigned from the region Xq27→qter to Xq26→q27 by quantitative in situ hybridization. The present study utilized a complex hybridization probe and prephotographed G-banded human chromosomes to improve analytical sensitivity and accuracy.

Murphy, P.D.; Miller, C.L.; Ruddle, F.H.

doi: 10.1159/000132120pmid: 4006514

Twenty-two HPRT-selected chromosome-mediated gene transfer lines were characterized by quantitative “dot” blotting. The range of human sequences in these lines extended from over 120,000 kb to less than 5,000 kb. One-half of these lines carried less than 16,000 kb.