Showing papers on "Chromosome 22 published in 1978"
TL;DR: A DNA·cDNA molecular hybridization assay is successfully used to directly determine the presence or absence of human β globin gene sequences in 20 human—mouse somatic cell hybrids, each of which contained a different subset of human chromosomes.
Abstract: We have successfully used a DNA·cDNA molecular hybridization assay to directly determine the presence or absence of human β globin gene sequences in 20 human—mouse somatic cell hybrids, each of which contained a different subset of human chromosomes. The assay is specific for the individual human globin genes and will detect the presence of a globin gene if the relevant chromosome is present in only 10% of the cells of a hybrid population. The content of human chromosomes in each hybrid clone was characterized by Giemsa 11 staining, Giemsa trypsin-Hoechst 33258 staining, and by the use of 22 independent isozyme markers for 17 different human chromosomes. All human chromosomes were present in one or more cell lines devoid of the human β globin gene except for 6, 8, 9, 11, and 13. Among these latter chromosomes, only chromosome 11 was present in the six hybrid clones that contained the human β globin gene. In fact, chromosome 11 was the only human chromosome that was present in all of the six hybrid clones found to be positive for the human β globin gene. Two sister clones, 157-BNPT-1 and 157-BNPT-4, had similar subsets of human chromosomes except that 11 was present only in 157-BNPT-4. 157-BNPT-4 contained the human β globin gene while 157-BNPT-1 did not. DNA from three hybrid lines was also annealed to purified human γ globin cDNA; two lines positive for human β globin gene sequences also contained human γ globin gene sequences while one line was negative for both β and γ gene sequences. On the basis of these results, the human β and γ globin genes have been assigned to human chromosome 11.
149 citations
TL;DR: A ‘male-specific’ DNA sequence has been localised to human satellite III DNA of the Y chromosome in what is believed to be the first case of its kind in the world.
Abstract: A ‘male-specific’ DNA sequence has been localised to human satellite III DNA of the Y chromosome.
117 citations
TL;DR: This paper discusses the application of B CHROMOSOME Nondisjunction to GENETIC STUDIES, and the applications of this technique to Gene Dosage and Gene Imprinling Studies.
Abstract: INTRODUCTION ........ ........ . . . . .. . . . . ...... ... 5 PROCESSES CONTROLLED BY THE B CHROMOSOME ........ . .. .. ....... ... 8 Nondisjunction 8 Preferential Fertilization , . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . ,. . . . . . . . . . . . ....... 11 Recombination 12 MOLECULAR AND CELLULAR BIOLOGY . . . . . 13 RELATIONSHIP TO ABNORMAL CHROMOSOME 10 IS APPLICATION OF B CHROMOSOME NONDISJUNCTION TO GENETIC STUDIES 16 Chromosome Mapping 16 Transfer of A Chromosome Segments Between Lines .. 16 Gene Dosage and Gene Imprinling Studies 17 SUMMARY ..... . . . . .. ......... ... . ....... 18
72 citations
TL;DR: A large autosomal region has been conserved in the evolution of mouse chromosome 4 and the short arm of human chromosome 1 and identification of such conserved regions will contribute to the understanding of the development of the mammalian genome and could suggest gene location by homology mapping.
Abstract: It is possible to generate interspecific somatic cell hybrids that preferentially segregate mouse chromosomes, thus making possible mapping of mouse genes. Therefore, comparison of the linkage relationships of homologous genes in man and mouse is now possible. Chinese hamster × mouse somatic cell hybrids segregating mouse chromosomes were tested for the expression of mouse enolase (ENO-1; EC 4.2.1.11, McKusick no. 17245), 6-phosphogluconate dehydrogenase [PGD; EC 1.1.1.44, McKusick no. 17220], phosphoglucomutase-2 (PGM-2; EC 2.7.5.1, McKusick no. 17190), and adenylate kinase-2 (AK-2; EC 2.7.4.3, McKusick no. 10302). In man, genes coding for the homologous forms of these enzymes have been assigned to the short arm of human chromosome 1. Analysis of 41 primary, independent, hybrid clones indicated that, in the mouse, ENO-1 and AK-2 are syntenic with PGD and PGM-2 and therefore can be assigned to mouse chromosome 4. In contrast, they were asyntenic with 21 other enzymes including mouse dipeptidase-1 (DIP-1, human PEP-C; EC 3.4.11.*, McKusick no. 17000) assigned to human chromosome arm 1q and mouse chromosome 1. Karyologic analysis confirmed this assignment. These data demonstrate that a large autosomal region (21 map units in the mouse and 51 map units in the human male) has been conserved in the evolution of mouse chromosome 4 and the short arm of human chromosome 1. Identification of such conserved regions will contribute to our understanding of the evolution of the mammalian genome and could suggest gene location by homology mapping.
71 citations
TL;DR: It is concluded that this sequence is related to human satellite III, but shows considerable differences in structure.
65 citations
TL;DR: It is shown that individual men are polymorphic for the amount of two different repeated DNA sequences, proportional to the length of the brightly fluorescent heterochromatin on the Y chromosome.
Abstract: We show that individual men are polymorphic for the amount of two different repeated DNA sequences. The amount of one of these sequences is proportional to the length of the brightly fluorescent heterochromatin on the Y chromosome. There are no detectable alterations in sequence between polymorphic individuals. Female DNA contains sequences complementary to those found on the Y, but at a much reduced level.
59 citations
TL;DR: The results obtained using in situ labeling and Ag-staining and association frequency indicated that the 14p+ chromosome had no greater nucleolus organizer activity than did the other acrocentrics; the difference in these findings suggests that not all the rRNA genes on the 14P+ chromosome were active.
Abstract: Chromosome studies were carried out on normal individuals from three generations of one family with a 14p+ chromosome. The short arm of the 14p+ chromosome stained well using Giemsa but poorly using quinacrine or trypsin-Giemsa methods; in each case there was an unstained secondary constriction near the distal end of the short arm. Two Ag bands of average size were present on the 14p+ short arm, indicating that there were two active nucleolus organizer regions; the Ag band near the distal end of the short arm was slightly larger than that near the centromere. Each of the two Ag bands was seen associated with the short arm of one or more of the other acrocentric chromosomes, with a combined frequency of association no greater than that of other chromosomes with an Ag band of the same size. In one individual, hybridization in situ with radioactive 18S and 28S ribosomal RNA showed six times as many autoradiographic silver grains over the short arm of the 14p+ chromosome as over that of any other acrocentric chromosome. The results obtained using in situ labeling indicated that the 14p+ chromosome had a large number of rRNA genes compared with the other acrocentric chromosomes, whereas the results obtained using Ag-staining and association frequency indicated that the 14p+ chromosome had no greater nucleolus organizer activity than did the other acrocentrics. The difference in these findings suggests that not all the rRNA genes on the 14p+ chromosome were active.
58 citations
TL;DR: Cellular autoradiography was used to measure relative rates of chromosomal RNA synthesis and to examine the regulatory phenomenon of X-linked dosage compensation in Drosophila miranda, a species containing two distinct, nonhomologous X chromosomes, finding the X1 chromosome to be dosage-compensated.
Abstract: Cellular autoradiography was used to measure relative rates of chromosomal RNA synthesis and to examine the regulatory phenomenon of X-linked dosage compensation in Drosophila miranda, a species containing two distinct, nonhomologous X chromosomes (X1 and X2). The X1 chromosome was found to be dosage-compensated, since the rate of RNA synthesis along the single X1 chromosome in males equaled that of both X1 chromosomes in females. Unlike other sex chromosomes that have been studied, the more recently evolved X2 heterochromosome exhibited regional differences in transcriptional activity when males and females were compared. The distal 10% of the X2 was not dosage-compensated, whereas the majority of an interior segment, representing 30% of the X2 chromosome's length, was found to be dosage-compensated. Our data are consistent with the idea that the evolution of X2 dosage compensation has paralleled the differentiation of the X2 sex chromosome. In addition, gene rearrangement seems to have accompanied the acquisition of a dosage-compensory mechanism in the X2.
48 citations
TL;DR: The arrangement of SV40 DNA sequences integrated in human chromosome 7 in two lines of mouse-human somatic cell hybrids is analyzed and it is found that the integration site differs in both the viral and host sequences in the two clones.
47 citations
TL;DR: The results confirmed that a gene, Bevi, previously assigned to human chromosome 6, dominantly controls baboon type C virus expression in hybrid cells, and concluded that Bevi is a preferred integration site for the baboontype C provirus in the human genome.
44 citations
TL;DR: The meiotic behaviour of a balanced translocation involving the short arms of chromosomes 5 and 22 has been analyzed by reconstructions of lateral components and synaptonemal complexes at early and mid pachytene in human spermatocytes to conclude that the translocation is reciprocal with transfer of the telomere region from chromosome 22 to chromosome 5 and that of the latter to chromosome 22.
Abstract: The meiotic behaviour of a balanced translocation involving the short arms of chromosomes 5 and 22 has been analyzed by reconstructions of lateral components and synaptonemal complexes at early and mid pachytene in human spermatocytes. At early pachytene, the normal chromosome 5 and the segment translocated onto chromosome 22 are paired with a synaptonemal complex in all 8 nuclei reconstructed, while pairing between the normal chromosome 22 and the translocation chromosome 5 was never observed. The pairing pattern was less regular at mid pachytene where a quadrivalent was observed in only 3 out of the 4 nuclei analyzed, while in the fourth nucleus, pairing was in part nonhomologous: the segment translocated onto chromosome 22 exhibited foldback pairing with itself and the short arm of the normal chromosome 5 was paired with the differential segment of the X chromosome. The short arms of translocation chromosome 5 and the normal chromosome 22 were paired in only one mid pachytene nucleus. Translocation chromosome 5 possessed in all 4 nuclei a 200 nm long terminal region of condensed chromatin resembling the heterochromatin of the short arms of the acrocentric chromosomes. This together with the observation that the telomere of the short arm of translocation chromosome 5 was attached to the nuclear envelope permits the conclusion that the translocation is reciprocal with transfer of the telomere region from chromosome 22 to chromosome 5 and that of the latter to chromosome 22. Recombination nodules were more frequent in bivalent 5 than in the remainder of the genome whereas a similar increase in nodule frequency was not observed for bivalent 22.
TL;DR: Chain and ring chromosome configurations were detected in a small percentage of the lymphocytes of a patient suffering from Thiberge-Weissenbach syndrome, suggesting a relationship between these configurations and the chromosome arrangement in the interphase nucleus is possible.
Abstract: Chain and ring chromosome configurations were detected in a small percentage of the lymphocytes of a patient suffering from Thiberge-Weissenbach syndrome. Precise recognition of the chromosomes involved in the rearrangements did not indicate a systematic order of end-to-end fusions. A relationship between these configurations and the chromosome arrangement in the interphase nucleus is possible.
TL;DR: It appears as though the elevation of iso-2-cytochrome c is caused by an abnormal controlling region adjacent to the structural region of the CYC7 gene.
Abstract: The CYC7-1 mutation in the yeast Saccharomyces cerevisiae causes the production of approximately 30 times the normal amount of iso-2-cytochrome c. Genetic analysis established that the CYC7-1 mutation is a reciprocal translocation involving the left arm of chromosome V and the right arm of chromosome XVI. The chromosome V arm was broken adjacent to the gene CYC7, which determines the primary structure of iso-2-cytochrome c, and this fragment containing the CYC7 gene was joined to the segment of chromosome XVI. It appears as though the elevation of iso-2-cytochrome c is caused by an abnormal controlling region adjacent to the structural region of the CYC7 gene.
TL;DR: In thirteen independent man-hamster hybrids, the human enzyme DIA1 presented a positive correlation with the human chromosome G22, and it is assumed that this newly assigned locus codes for both soluble and microsomal forms of NADH-cytochrome b5 reductase.
Abstract: NADH-cytochrome b5 reductase (DIA1, EC. 1.6.2.2) from human fibroblasts and from Chinese hamster cells, both identified by immunologic studies, were clearly distinguished after polyacrylamide gel isoelectrofocusing followed by staining for NADH diaphorase activity. In thirteen independent man-hamster hybrids, the human enzyme DIA1 presented a positive correlation with the human chromosome G22. Eight hybrids were DIA1(+) G22(+) and five hybrids were DIA1(-) G22(-). These data agree with the recent assignment of DIA1 to chromosome G22 by Fisher et al. (1977a). We assume that this newly assigned locus codes for both soluble and microsomal forms of NADH-cytochrome b5 reductase.
TL;DR: Chromosome configurations were recorded in about 5500 pollen mother cells (PMC's) in 2n and 2n-1 heterozygotes of ten reciprocal translocations involving six A-genome chromosomes of Gossypium hirsutum to derive a karyotype in reasonably good agreement with data from genetic mapping, telosome and monosome mapping, and the mitotic idiogram.
Abstract: Chromosome configurations were recorded in about 5500 pollen mother cells (PMC's) in 2n and 2n-1 (missing the intact A-genome chromosome) heterozygotes of ten reciprocal translocations involving six A-genome chromosomes (H1, H2, H3, H4, H6 and H7) and six D-genome chromosomes (H14, H15, H16, H19, H20 and H21) of Gossypium hirsutum. From these records, chiasma frequencies at each of six positions were determined for nine translocations and at two positions for one. These frequencies were used to calculate recombination frequencies in different chromosome regions, and from these distances the breakpoints in 15 chromosome arms were mapped relative to each other and to their respective centromeres, insofar as the data permitted. The karyotype so derived for twelve chromosomes is in reasonably good agreement with data from genetic mapping, telosome and monosome mapping, and the mitotic idiogram.
TL;DR: Evidence is presented for the assignment of the gene for adenosine kinase to Mus musculus chromosome 14 by synteny testing and karyotypic analysis of mouse X Chinese hamster somatic cell hybrid clones and Chromosome analysis confirmed this assignment.
Abstract: Evidence is presented for the assignment of the gene for adenosine kinase to Mus musculus chromosome 14 by synteny testing and karyotypic analysis of mouse X Chinese hamster somatic cell hybrid clones. ADOK and two enzymes previously mapped to mouse chromosome 14, NP and ES-10, were expressed concordantly in 29 hybrid clones. Chromosome analysis confirmed this assignment. Syntenic evidence is also presented using several clones of a gene transfer system in which the gene for human HPRT had integrated into modified mouse chromosome 14’s.
TL;DR: The significance of the heavy labelling of lampbrush loops near centromeres and on the heteromorphic arms of the newt chromosome I is discussed in relation to possible cytological and molecular mechanisms for generating and preserving families of tandemly linked and cytologically localized m.r. sequences.
Abstract: The general features of the arrangement and cytological distribution of repeated sequences in animal chromosomes are reviewed. These features include internal repetitiveness, conservation of clearly functional sequences, rapid divergence of certain classes of repeated sequence with subsequent fixation of families of diverged sequences, and well defined cytological localization of large blocks of sequences in specific parts of the chromosome set. Moderately or 'middle' repetitive (m.r.) sequences constitute a large part of the genomes of higher organisms, they seem to accumulate in a balanced manner within chromosome sets, they are mainly responsible for genome growth, and they are interspersed with sequences of other kinds. Little is known about their cytological distribution. Four experiments are described, each of which aimed to locate middle repetitive sequences in the chromosomes of a salamander and a newt. Tritiated m.r. DNA from Plethodon cinereus binds in a non-random fashion to the meiotic diplotene and mitotic chromosomes of the same species, suggesting a non-random distribution of m.r. sequences on these chromosomes. The same DNA, hybridized in situ to the RNA transcripts on the loops of lampbrush chromosomes, produces light and widespread labelling of many loops, but intense labelling of six pairs of loops, each of which lies near to a centromere. Similar experiments in which newt m.r. DNA was hybridized in situ to newt lampbrush chromosomes showed heavy labelling of about 30 loop pairs on each of the long heteromorphic arms of chromosome I, but very little labelling elsewhere. Autoradiographs of newt mitotic chromosomes hybridized with newt m.r. DNA showed rather even labelling of all chromosomes including chromosome I. The significance of the heavy labelling of lampbrush loops near centromeres and on the heteromorphic arms of the newt chromosome I is discussed in relation to possible cytological and molecular mechanisms for generating and preserving families of tandemly linked and cytologically localized m.r. sequences.
TL;DR: An interesting finding was the presence of extra ribosomal DNA and satellite DNAs I, II and III in one chromosome 22 which was found in seven out of nine individuals of the family with the 13:14 translocation, and in only one of five individuals without the translocation.
Abstract: In a family with a stable dicentric 13:14 translocation chromosome, the distribution of DNA sequences complementary to satellite DNAs I, II and III and ribosomal RNA were studied. The translocation chromosome showed a loss of sequences complementary to all three satellite DNAs, located in the short arms of all the acrocentric chromosomes, but slightly more of the sequences complementary to satellite I were retained than of the other two satellite DNAs. The fact that material was lost from all three satellites indicates that they are not present as single discrete blocks in these chromosomes, when we would expect to find the distal sequences lost and the proximal ones retained, but consist of interspersed blocks with each sequence represented by more than one, and probably several blocks. There was a total loss of ribosomal DNA from the nucleolar organiser regions of the chromosomes involved in the 13:14 translocation, but an interesting finding was the presence of extra ribosomal DNA and satellite DNAs I, II and III in one chromosome 22 which was found in seven out of nine individuals of the family with the 13:14 translocation, and in only one of five individuals without the translocation. There may be a compensatory mechanism present when certain sequences are eliminated during chromosomal rearrangements. The relationship of such mechanisms to reproductive fitness is discussed.
TL;DR: The chromosome investigations showed that human chromosome 14 was consistently involved in all three EBV genome-positive and EBNA-positive hybrid clones, but not in any negative clones, suggesting that this particular chromosome alone is sufficient for the maintenance and the expression of EBV genetic information in human lymphoblastoid cells.
Abstract: Fourteen hybrid clones derived from the fused cultures of human lymphoblastoid FV5 cells and 5-bromodeoxyuridine-resistant mouse fibroblastic MCB2 cells grown in hypoxanthine/aminopterin/thymidine selective medium were examined for the presence of Epstein-Barr virus (EBV) DNA, the expression of the virus-determined nuclear antigen (EBNA), and the presence of human chromosomes, in the course of serial passage in vitro. Among the hybrid clones tested, 3 were positive for EBV DNA and EBNA, whereas the remaining 11 were totally negative. The chromosome investigations showed that human chromosome 14 was consistently involved in all three EBV genome-positive and EBNA-positive hybrid clones, but not in any negative clones. In 10 subclones isolated from 1 of the 3 positive clones, all of which contained only chromosome 14 of the human chromosomes, a concordant segregation of EBNA, EBA DNA, and chromosome 14 was evident. These findings suggest that the resident EBV genome is closely associated with chromosome 14 and the presence of this particular chromosome alone is sufficient for the maintenance and the expression of EBV genetic information in human lymphoblastoid cells.
TL;DR: The results show that the structural gene for humanα-galactosidase B is situated on chromosome 22, and that there is no structural relationship between human α-galactsidase A and human β-galacticase B.
Abstract: The localization of the structural gene for human α-galactosidase B (=N-acetyl-α-galactosaminidase) was investigated by means of man-Chinese hamster and man-mouse somatic cell hybrids. The hybrid clones were analyzed for chromosomes and for a large number of known enzyme markers. The lysates of the hybrid cells were treated with Sepharose-coupled antihuman α-galactosidase B and the activity of the adsorbed enzyme was measured on the Sepharose beads as N-acetyl-α-galactosominidase. The results show that the structural gene for human α-galactosidase B is situated on chromosome 22, and that there is no structural relationship between human α-galactosidase A and human α-galactosidase B.
TL;DR: As in the proband, the association frequency remained constant because of an increased association tendency of chromosomes 22, the possibility is discussed that the loss of NORs was compensated by a higher NOR activity of one chromosome 22.
Abstract: NOR activity in a proband with 13/13 translocation and in her relatives was examined by NOR silver impregnation and by determination of the association frequencies. In the proband, besides the fused chromosomes 13, also a chromosome 14 and a 15 showed no NOR staining. Therefore the possiblity could be ruled out that the loss of NORs was compensated by the activation of inactive NORs. However, in the proband, one chromosome 22 seemed to be more intensively stained by silver nitrate than in her parents. As in the proband, the association frequency remained constant because of an increased association tendency of chromosomes 22. The possibility is discussed that the loss of NORs was compensated by a higher NOR activity of one chromosome 22.
TL;DR: The binding of 3H-AMD to the metaphase chromosomes of Drosophila melanogaster has been analyzed after two different periods of exposure to photographic emulsion and it is suggested that the specific underlabelling of the Y chromosome reflects a peculiar AT richness.
Abstract: The binding of 3H-AMD to the metaphase chromosomes of Drosophila melanogaster has been analyzed after two different periods of exposure to photographic emulsion. The entirely heterochromatic Y chromosome was markedly less labelled than euchromatin and other heterochromatic regions. Moreover, the few grains present on the Y chromosome were clustered in two regions, one localized in the middle of YS and the other in the proximal third of YL. This labelling pattern is not affected by removing histones with a 2-hour treatment with 2N HCl. It is suggested that the specific underlabelling of the Y chromosome reflects a peculiar AT richness.
TL;DR: A review of 12 cases of the Philadelphia chromosome originating by the rearrangement of three or more chromosomes reveals that chromosomes 9 and 22 are always involved, while the third chromosome is a different one in each case.
Abstract: A woman with chronic myelocytic leukemia had the Philadelphia chromosome and a complex four-break—three-chromosome rearrangement. The q32→q34 portion of chromosome 9 is translocated to band q22 of chromosome 7, and at the end of this segment is attached the deleted q11→ qter portion of chromosome 22. A review of 12 cases of the Philadelphia chromosome originating by the rearrangement of three or more chromosomes reveals that chromosomes 9 and 22 are always involved, while the third chromosome is a different one in each case. We discuss the hypothesis that the 22q segment is always specifically attached to band 9q34 wherever this portion of 9q is transposed.
TL;DR: Assignment of human genes coding for α-fucosidase (αFUC) and glucose dehydrogenase (GDH) to chromosome 1 has been confirmed and a location in the p21→pter region demonstrated using man-mouse somatic cell hybrids.
Abstract: Assignment of human genes coding for α-fucosidase (αFUC) and glucose dehydrogenase (GDH) to chromosome 1 has been confirmed and a location in the p21→pter region demonstrated using man-mouse somatic cell hybrids. The regional location af αFUC andGDH was established in cell hybrids using human cells possessing 1/2 translocation chromosomes [46,XX,t(1;2)(p21;q37)]. Hybrids which retained the 2q+ chromosome carrying the 1p21→1pter region concordantly expressed αFUC, GDH, and the short-arm markers ENO1, AK2, and PGM1. Hybrids which retained the 1p21→1qter region only expressed human PEPC and FH. Data obtained from hybrids in which spontaneous breaks in chromosome 1 had occurred indicate that the gene order in 1p21ar1pter is (ENO1,GDH)-αFUC-AK2-PGM1.
TL;DR: In this article, the authors dealt with a mother who is a carrier of a reciprocal translocation between chromosome 22 and 10, which has resulted in two children with a 10p trisomy.
Abstract: Since the usefulness of chromosome differential banding techniques has become fully established, several descriptions of chromosome 10 short arm trisomy have been published (Schleiermacher et al., 1974; Roux et al., 1974; Cantu et al., 1975; Grosse et al., 1975; Moric-Petrovic et al., 1976; Turleau et al., 1976; Johnson et al., 1977; Yunis and Lewandowski, 1977). The present report deals with a mother who is a carrier of a reciprocal translocation between chromosome 22 and 10, which has resulted in two children with a 10p trisomy.
TL;DR: The existence of different types of Y chromosome staining patterns was explained on the basis of the previously described hypothesis of unequal distribution of thymine residues between two DNA polynucleotide chains in the distal part of the long arms of human Y chromosomes.
Abstract: Isolabeling segments were found in the distal region of the long arm of Y chromosomes derived from human leukocytes grown through two replication cycles in medium containing BrdU and stained by the FPG technique Three main types of Y chromosome staining patterns were demonstrated: I-Y chromosome with typical SCD, II-Y chromosome with weakly stained distal regions of long arms (isolabeling segments), III-Y chromosome with both terminal regions displaying SCD interrupted by one isolabeled segment The existence of different types of Y chromosome staining patterns was explained on the basis of the previously described hypothesis of unequal distribution of thymine residues between two DNA polynucleotide chains in the distal part of the long arms of human Y chromosomes
TL;DR: Cytogenetic family studies showed that the mother is a carrier of a balanced reciprocal translocation t(13;22), which does not affect the size and morphology of the chromosomes involved.
Abstract: A family is reported in which the propositus has an extra G-like chromosome with an unusual G-banding pattern. Cytogenetic family studies showed that the mother is a carrier of a balanced reciprocal translocation t(13;22), which does not affect the size and morphology of the chromosomes involved. The propositus has a 47,XY,+der(22),t(13;22)(q22;q11) karyotype and is therefore partially trisomic for the distal third of the long arm of chromosome 13 and for a very small part of chromosome 22. The clinical findings are presented and compared with those of other reported cases of partial trisomies 13 and 22.
TL;DR: The pattern of terminal replication of the human chromosomes in a clone of hybrids between diploid human fibroblasts and mouse cells was analyzed by autoradiography and suggested that the sequence of terminal chromosome replication in human fibrosomes is not irreversibly programmed into each chromosome.
Abstract: The pattern of terminal replication of the human chromosomes in a clone of hybrids between diploid human fibroblasts and mouse cells was analyzed by autoradiography. An average of 10 human chromosomes was present in the hybrid cells. Several of these chromosomes were found to terminate replication in a different order from the same chromosomes in the parental human fibroblasts. Chromosomes 4 and 5 completed replication later in the hybrid than in the fibroblasts (relative to the other human chromosomes). In contrast, chromosomes 7, 12, and 15 completed replication earlier in the hybrid than in the fibroblasts. These results suggest that the sequence of terminal chromosome replication in human fibroblasts is not irreversibly programmed into each chromosome.