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Results for “interspecific hybridization”

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At least 19 recordsLinked to original sources
PubMed2025

Genome diversity and evolution of the duckweed section Alatae comprising diploids, polyploids, and interspecific hybrids.

The section Alatae of genus Lemna of the monocotyledonous aquatic duckweed family (Lemnaceae) consists of rather diverse accessions with unknown phylogeny and unclear taxonomic assignment. In contrast to other duckweeds, some Alatae accessions, in addition to mainly vegetative propagation, produce readily flowers and viable seeds. We analyzed the genomic diversity and phylogenetic relationship of 52 Alatae accessions. For this purpose, we applied multiple molecular and cytogenetic approaches, including plastid and nuclear sequence polymorphisms, chromosome counting, genome size determination, and genomic in situ hybridization in combination with geographic distribution. We uncovered ploidy variation, recurrent hybridization, and backcrosses between species and their hybrids. The latter successfully spread over three continents. The results elucidate the evolution of Alatae accessions and explain the difficult taxonomic assignment of distinct accessions. Our study might be an example for analogous studies to resolve the hitherto unclear relationships among accessions of the duckweed genera Wolffiella and Wolffia.

Araceae↗
PubMed1979

Induced segregation in interspecific hybrids of Aspergillus nidulans and Aspergillus rugulosus obtained by protoplast fusion.

Interspecific hybrids produced by polyethylene glycol induced fusion of protoplasts from auxotrophic mutants of Aspergillus nidulans and Aspergillus rugulosus were grown in the presence of the recombinogens benomyl and chloral hydrate to stimulate segregation. The A. nidulans parental strains used had a known genetic marker in each linkage group. Hybrids grown on complete medium containing benomyl yielded more segregants. Analysis of the segregants showed that the distribution of A. nidulans linkage groups was random. No specific linkage group appeared in all the segregants. The two parents are closely related taxonomically and the findings from these experiments suggest that a high degree of chromosomal homology may exist between them.

Aspergillus↗
PubMed1978

Inheritance and linkage analysis of five enzyme loci in interspecific hybrids of toadlets, genus Bombina.

Progeny produced from Bombina bombina, B. variegata, and field-collected interspecific hybrids have been analyzed for the inheritance of five enzyme loci, which are fixed for alternate alleles in the parental species. Lactate dehydrogenase (Ldh-1), NAD-dependent malate dehydrogenase (Mdh-1), creatine kinase (Ck), adenylate kinase (Ak), and glucosephosphate isomerase (Gpi) are all inherited in a Mendelian manner as codominant alleles at nuclear loci. Both parental alleles are equally functional in artificial F1 hybrids (female B. bombina x male B. variegata) at each of the loci studied. No linkage between any pair of loci was observed. Discovery of this inherited biochemical variation combined with a technique for assaying individual genotypes without killing the animals makes feasible studies of hybrid population structure heretofore impossible.

Adenylate Kinase↗
PubMed1977

[Electrophoretic analysis of lactate NAD oxidoreductase in interspecific hybrids between three species of the genus Sphaeroma: S. monodi, S. Rugicauda and S. hookeri].

The electrophoretic analysis of lactate NAD oxydoreductase in interspecific hybrids between three species of genus Sphaeroma (S. monodi, S. rugicauda and S. hookeri hookeri) leads, for each category of hybrids, to a distribution between the two parental enzymatic patterns and, consequently, shows the absence of an isozyme appropriate to these hybrids.

Animals↗
PubMed1977

Development of interspecific hybrids of Mus.

Artificial insemination has been used to produce interspecific mouse hybrids. Mus musculus x Mus cervicolor cervicolor hybrids failed to complete more than a few cleavage divisions but both M. musculus x M. dunni and M. musculus x M. caroli hybrids completed preimplantation development. These hybrid embryos are heterozygous for various X-linked enzymes and may provide a useful genetic system for studying X-chromosome inactivation during early development. Further development of M. muscuius x M. caroli hybrids was studied: several completed foetal development; a few survived to maturity but none has yet reproduced.

Animals↗
PubMed1976

Chromosomally depleted interspecific hybrid cell clones selected with cytotoxic antisera: utilization in the study of control of murine leukemia virus host-range.

A chromosomally stable mouse-Chinese hamster hybrid cell line was subjected to five rounds of selection with cytotoxic antisera raised in rabbits against either the parental mouse 3T3 cells or the parental Chinese hamster Wg-1 cells. Routine karyological analysis of clones isolated at each stage of serum selection revealed that treatment with either serum resulted in a limited loss of chromosomes (compared to the untreated hybrid cell cultured in parallel) and that the pattern of chromosome loss could not be correlated with the particular antiserum used for selection. However, more detailed analysis with the SSC-formamide C-banding technique, which identifies chromosomes containing a mouse centromere region, demonstrated that while large-scale chromosome loss was not achieved as a result of antiserum selection, the limited loss of chromosomes did, in fact, reflect a specific depletion of chromosomes in response to treatment with cytotoxic antiserum. Specific chromosomal elimination was shown to occur as early as the first round of antiserum treatment. Antigenic analysis of the serum-selected clones revealed a quantitative decrease in the expression of the species-specific surface antigens selected against, but no qualitative loss of antigens was detected. The results suggest that treatment with cytotoxic antiserum may select for clones that have lost specific chromosomes bearing genes regulating the expression of species-specific surface antigens, rather than for those demonstrating large-scale depletion of chromosomes bearing the corresponding structural genes. Some of these chromosomally depleted hybrid cell clones have been used (along with pseudotype viruses containing the genome of vesicular stomatitis virus within the envelope of murine leukemia virus, VSV [MuLV]), to study the mechanisms regulating MuLV replication in Chinese hamster cells. The results indicate that the restriction of MuLV replication in Chinese hamster cells operates at two levels: (a) an inability to adsorb to or penetrate Chinese hamster cells; and (b) an additional intracellular block which is dominant in the mouse-Chinese hamster hybrid cell clones examined. This latter block is presently under study.

Antigens↗
PubMed1977

[Regional localization of the genes for human IDHs, MDHs PGK, alphaGAL, G6PD by interspecific hybridization (author's transl)].

22 independent man-hamster (HGPRT-) hybrids using male human cells with balanced reciprocal translocation t(X;2)(p22;q32) were analysed for human genes localized on chromosome 2 (IDHs, MDHs), on chromosome X (PGK, alphaGAL, G6PD) and for the different chromosomes in relation with the balanced reciprocal translocation (chr.2, chr.2q-, chr.Xp+). The following results were obtained: The chromosomes 2 and 2q- are absent in the 22 hybrids. In 9 hybrids, the absence of MDHs in spite of the presence of the chromosome Xp+ indicates that the gene for MDHs is not localized on this chromosome (or that the gene for MDHs is not on the segment 2q32--2qter translocated on X). In 14hybrids, the three markers of X (PGK, alphaGAL, G6PD) and IDHs are expressed in the presence of the chromosome Xp+. This result indicates that the genes for these markers are on Xp+ or that the genes PGK, alphaGAL, G6PD are on X without the Xp22--Xter segment, translocated on the chr.2, and that the gene for IDHs is on the 2q32--2qter segment translocated on X. In 8 hybrids, in the absence of the intack chromosome Xp+, the higher percentage of the presence of G6PD (7 hybrids) and the lower percentage of the presence of IDHs (3 hybrids) are explained by the fact that these hybrids selected in HAT medium had to retain a segment of Xp+ bearing the human gene HGPRT. G6PD appeared very close to HGPRT and IDHs very distant from HGPRT. The study of the different correlations between the presence and the absence of these four markers on Xp+ in the different hybrids indicates the following order on the chromosome Xp+ from p to q: IDHs -- PGK --alphaGAL -- G6PD.

Animals↗
PubMed1979

[Localization of the gene for phosphoglycolate phosphatase (PGP) on the chromosome 16 by interspecific hybridization (author's transl)].

Eight primary man-mouse (C11D/TK-) hybrids, twenty three primary and seven secondary man-hamster (CH/HGPRT-) were analyzed for human phosphoglycolate phosphatase (PGP) and for human chromosomes. The following results were obtained: 1. A positive correlation is observed between the chromosome 16 and PGP. 15 hybrids are chr.16+PGP+, 14 hybrids are chr.16-PGP- and 4 hybrids are chr.16-PGP+. 2. The percentage of dissociation between PGP and the chr.16 is low (12%) in comparison with the high percentage of dissociation between PGP and the other autosomes (between 37% and 65%). 3. Excepted the chromosome 16, the other autosomes are observed in hybrids PGP-. These different results indicate the localization of the gene for human PGP on the chromosome 16. The dissociation results chr.16-PGP+ are explained by the breakage of the chr.16 in the hybrids.

Animals↗
PubMed1976

Intrachromosomal gene mapping in man: assignment of nucleoside phosphorylase to region 14cen leads to 14q21 by interspecific hybridization of cells with a t(X;14) (p22;q21) translocation.

The structural gene for purine-nucleoside phosphorylase (NP) has been assigned to a subregion of chromosome 14 by somatic cell hybridization of male and female cells containing the balanced translocation t(X;14) (p22;q21). Peripheral lymphocytes were fused to a pseudodiploid HPRT-deficient established Chinese hamster cell line. 23 primary hybrid clones (10 derived from male and 13 from female cells) were isolated and maintained in HAT selective medium. Parallel subcultures from generations 16, 24, and 40 after clonal isolation were fully karyotyped and analyzed electrophorectically for expression of the human types of NP, HPRT, G6PD, and PGK. The human NP phenotype segregated discordantly with each human chromosome except chromosome 14 and the der(14),t(X;14) translocation chromosome. In all, 8 hybrids which had retained the der(X), t(X;14) translocation chromosome under HAT selective pressure and expressed human HPRT had lost the human NP phenotype. These results indicate localization of the NP gene in region 14pter leads to 14q21.

Adenine Phosphoribosyltransferase↗
PubMed1975

A study of hexosaminadases in interspecific hybrids and in GM2 gangliosidosis with a discussion on their genetic control.

1. Hexosaminidases were studied by electrophoresis with different human fibroblast extracts. We found in the same conditions of detection and culture three bands from the cathode to the anode, namely Hex B, Hex A, Hex C for the normal fibroblast, Hex B for the two different Tay-Sachs and Hex C for the two unrelated Sandhoff patients. 2. The analysis of man-rodent hybrids (hamster and mouse with normal and Sandhoff human fibroblasts) indicates a probable synteny between MPI, Hex C, "Hex A fast", and "Hex A-like". "Hex A fast" is probably a man-hamster hybrid enzyme, "Hex A-like" a man-mouse enzyme. Our data agree with the model of Ropers and Schwantes (Hex C = (alphaalpha)n; Hex A = (alphabeta)n; Hex B = (betabeta)n). Probably Hex A-fast = (alphabeta')n with hamster Hex B' = (beta'beta')n; and Hex A-like = (alphabeta1)n with mouse Hex B1 = (beta1beta1)n; and probably n = 2 according to the tetrameric structure model of Tallman et al. (1974). 3. As an explanation of the results given by Poenaru et al. (anti Hex A reacts with Hex A and Hex B but not with Hex C) we propose the existence of a compound antigen (alphabeta) for Hex A. Anti Hex A specific = anti (alphabeta); anti Hex A non-specific = anti Hex B = anti B, anti alpha being absent or negligible. 4. In our opinion, the Tay-Sachs mutation opposes the alphaB association while the alphaalpha association is possible at a low rate or unstable; it is thus possible to observe Hex C in certain conditions, e.g. in foetal brain. 5. We present a discussion about the genetic control of hexosaminidases, GM2 gangliosidosis, and the possible localization of the different mutations in the variants.

Animals↗
PubMed1976

Tryptophan operon regulation in interspecific hybrids of enteric bacteria.

We examined tryptophan regulation in merodiploid hybrids in which a plasmid carrying the trp operon of Escherichia was introduced into Trp mutants of other enteric genera, or in which a plasmid carrying the trpR+ (repressor) gene of E. coli was transfered into fully constitutive trpR mutants of other genera. In these hybrids the trp operon of one species is controlled by the repressor of a different species. Similar investigations were possible in transduction hybrids in which either the trp operon or the trpR+ locus of Shigella dysenteriae was introduced into E. coli. Our measurements of trp enzymes levels in repressed and nonrepressed cells indicate that Trp regulation is normal, with only minor quantitative variations, in hybrids between E coli and Shigella dysenteriae, Salmonella typhimurium, Klebsiella aerogenes, Serratia marcescens, and Proteus mirabilis. Our results support the idea that a repressor-operator mechanism for regulating trp messenger ribonucleic acid production evolved in a common ancestor of the enteric bacteria, and that this repressor-operator recognition has been conversed during the evolutionary divergence of the Enterobacteriaceae.

Anthranilate Phosphoribosyltransferase↗
PubMed1977

Chromosomal evolution in Malagasy lemurs. II. Meiosis in intra- and interspecific hybrids in the genus Lemur.

The chromosome analysis of meiosis in four lemurs, Lemur fulvus fulvus, L. f. collaris, L. f. albocollaris, and L. macaco, and particular hybrid crosses is reported. In metaphase I, trivalents and chain elements were detected and identified with T-banding. The study largely confirms our previous work on mitotic karyotype comparisons in the genus Lemur. The absence of chain multivalents elements in the pachytene stages of hybrid meiosis, where a chain is detected later in diakinesis, may offer evidence on the possible existence of a two-step pairing mechanism in meiotic homolog pairing. Considerations about the role of the chromosome rearrangements in establishing a gametic barrier in speciation are developed.

Animals↗