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F Grützner

Publications and source records attributed to F Grützner.

At least 19 recordsLinked to original sources
PubMed2006

Construction of a highly enriched marsupial Y chromosome-specific BAC sub-library using isolated Y chromosomes.

The Y chromosome is perhaps the most interesting element of the mammalian genome but comparative analysis of the Y chromosome has been impeded by the difficulty of assembling a shotgun sequence of the Y. BAC-based sequencing has been successful for the human and chimpanzee Y but is difficult to do efficiently for an atypical mammalian model species (Skaletsky et al. 2003, Kuroki et al. 2006). We show how Y-specific sub-libraries can be efficiently constructed using DNA amplified from microdissected or flow-sorted Y chromosomes. A Bacterial Artificial Chromosome (BAC) library was constructed from the model marsupial, the tammar wallaby (Macropus eugenii). We screened this library for Y chromosome-derived BAC clones using DNA from both a microdissected Y chromosome and a flow-sorted Y chromosome in order to create a Y chromosome-specific sub-library. We expected that the tammar wallaby Y chromosome should detect approximately 100 clones from the 2.2 times redundant library. The microdissected Y DNA detected 85 clones, 82% of which mapped to the Y chromosome and the flow-sorted Y DNA detected 71 clones, 48% of which mapped to the Y chromosome. Overall, this represented a approximately 330-fold enrichment for Y chromosome clones. This presents an ideal method for the creation of highly enriched chromosome-specific sub-libraries suitable for BAC-based sequencing of the Y chromosome of any mammalian species.

Animals↗
PubMed2006

Segmental duplication associated with evolutionary instability of human chromosome 3p25.1.

Fluorescence in situ hybridization (FISH) of human bacterial artificial chromosome (BAC) clones to orangutan metaphase spreads localized a breakpoint between human chromosome 3p25.1 and orangutan chromosome 2 to a <30-kb interval. The inversion occurred in a relatively gene-rich region with seven genes within 500 kb. The underlying breakpoint is closely juxtaposed to validated genes, however no functional gene has been disrupted by the evolutionary rearrangement. An approximately 21-kb DNA segment at the 3p25.1 breakpoint region has been duplicated intrachromosomally and interchromosomally to multiple regions in the orangutan and human genomes, providing additional evidence for the role of segmental duplications in hominoid chromosome evolution.

Animals↗
PubMed2005

Genomic structure and paralogous regions of the inversion breakpoint occurring between human chromosome 3p12.3 and orangutan chromosome 2.

Intrachromosomal duplications play a significant role in human genome pathology and evolution. To better understand the molecular basis of evolutionary chromosome rearrangements, we performed molecular cytogenetic and sequence analyses of the breakpoint region that distinguishes human chromosome 3p12.3 and orangutan chromosome 2. FISH with region-specific BAC clones demonstrated that the breakpoint-flanking sequences are duplicated intrachromosomally on orangutan 2 and human 3q21 as well as at many pericentromeric and subtelomeric sites throughout the genomes. Breakage and rearrangement of the human 3p12.3-homologous region in the orangutan lineage were associated with a partial loss of duplicated sequences in the breakpoint region. Consistent with our FISH mapping results, computational analysis of the human chromosome 3 genomic sequence revealed three 3p12.3-paralogous sequence blocks on human chromosome 3q21 and smaller blocks on the short arm end 3p26-->p25. This is consistent with the view that sequences from an ancestral site at 3q21 were duplicated at 3p12.3 in a common ancestor of orangutan and humans. Our results show that evolutionary chromosome rearrangements are associated with microduplications and microdeletions, contributing to the DNA differences between closely related species.

Animals↗
PubMed2003

Isolation of chromosomal regions controlling intersex development in a marsupial.

A marsupial (Sminthopsis douglasi) with bilateral intersexuality had a hemiscrotum on the right side and a hemi-pouch with nipples on the left. A normal female karyotype (2n = 14, XX) was present in cells from the right (male) side, while cells from the left (female) side initially had a female karyotype plus two dot-like chromosomes (2n = 14, XX + 2B). It is proposed that the dots represented a region deleted from the X chromosome that contains the "pouch-mammary/scrotum" (PMS) switch gene whose dosage determines development of a pouch and teats (two doses) or a scrotum (one dose). Mis-segregation early in embryonic development produced a lineage with one normal X and one deleted X (male side), and a lineage with a normal and deleted X, plus two copies of the deleted region (female side). The origin of the supernumerary elements was therefore investigated in the expectation that they may contain the long-sought pouch-mammary/scrotum switch gene. Several elements were microdissected, and amplified DNA was used for in situ hybridization, producing signals in five different chromosome regions including the X. This could represent a region of the X that contains, as well as PMS, repetitive DNA that is present also at other chromosomal sites.

Animals↗
PubMed2001

Species-specific evolution of repeated DNA sequences in great apes.

DNA sequencing reveals that the genomes of the human, gorilla and chimpanzee share more than 98% homology. Comparative chromosome painting and gene mapping have demonstrated that only a few rearrangements of a putative ancestral mammalian genome occurred during great ape and human evolution. However, interspecies representational difference analysis (RDA) of the gorilla between human and gorilla revealed gorilla-specific DNA sequences. Cloning and sequencing of gorilla-specific DNA sequences indicate that there are repetitive elements. Gorilla-specific DNA sequences were mapped by fluorescence in-situ hybridization (FISH) to the subcentromeric/centromeric regions of three pairs of gorilla submetacentric chromosomes. These sequences could represent either ancient sequences that got lost in other species, such as human and orang-utan, or, more likely, recent sequences which evolved or originated specifically in the gorilla genome.

Animals↗
PubMed2001

Comparative mapping of the human 9q34 region in Fugu rubripes.

Twenty-seven genes have been cloned and mapped in Fugu which have orthologues within the human chromosome 9q34 region. The genes are arranged into five cosmid and BAC contigs which physically map to two different Fugu chromosomes. Considering the gene content of these contigs, it is more probable that a translocation event took place early in the Fugu lineage to split the ancestral 9q34 region onto two chromosomes rather than the alternative hypothesis of a large-scale duplication of the region into two chromosomes with subsequent rapid and dramatic gene loss. There are considerable differences in gene order between the two species, which would appear to be the result of a series of complex chromosome inversions; thus suggesting that there have been no positional constraints on this particular gene set.

Animals↗
PubMed2001

Chicken microchromosomes are hypermethylated and can be identified by specific painting probes.

Microdissection of single chicken microchromosomes (MICs) followed by degenerate oligonucleotide-primed (DOP) PCR allows the rapid generation of MIC-specific DNA libraries. Since some libraries derived from a single (or a few) chromosome(s) label the entire MIC fraction, the majority of chicken MICs share repetitive DNA sequences that are not found on the macrochromosomes. In evolutionarily distant bird species, MICs are invariably hypermethylated. Methylcytosine staining provides additional in situ evidence for the high gene content of MICs and strong compartmentalization of avian genomes.

Animals↗
PubMed2000

Molecular cloning and characterization of the Fugu rubripes MEST/COPG2 imprinting cluster and chromosomal localization in Fugu and Tetraodon nigroviridis.

We isolated Fugu genomic clones using the human MEST (Mesoderm-Specific Transcript) cDNA as probe. Sequence analysis revealed the presence of MEST and three additional genes which show homology to plant DNBP (DNA-Binding Protein), vertebrate COPG2 (Coat Protein Gamma 2), as well as to human and mouse UCN (Urocortin). Structures of Fugu and human MEST, COPG2 and UCN genes are very similar. Since MEST and COPG2 are neighboring genes on human chromosome 7q32, we can conclude that we identified their orthologs and that linkage of these genes is evolutionarily conserved in vertebrates. Unlike human MEST which underlies isoform-specific imprinting and is methylated in a parent-of-origin-specific fashion, the CpG island of the Fugu ortholog is completely methylated. The translation start of Fugu MEST is identical to the non-imprinted human isoform which is in good agreement with the assumption that genomic imprinting is restricted to mammals. Comparative mapping of these genes by fluorescence in-situ hybridization to metaphase chromosomes of Fugu rubripes and Tetraodon nigroviridis showed clear signals on one of the smallest acrocentric chromosomal pairs, which in Fugu, can be easily classified by its unique triangular shape.

Amino Acid Sequence↗
PubMed2000

Conserved synteny between the chicken Z sex chromosome and human chromosome 9 includes the male regulatory gene DMRT1: a comparative (re)view on avian sex determination.

Sex-determination mechanisms in birds and mammals evolved independently for more than 300 million years. Unlike mammals, sex determination in birds operates through a ZZ/ZW sex chromosome system, in which the female is the heterogametic sex. However, the molecular mechanism remains to be elucidated. Comparative gene mapping revealed that several genes on human chromosome 9 (HSA 9) have homologs on the chicken Z chromosome (GGA Z), indicating the common ancestry of large parts of GGA Z and HSA 9. Based on chromosome homology maps, we isolated a Z-linked chicken ortholog of DMRT1, which has been implicated in XY sex reversal in humans. Its location on the avian Z and within the sex-reversal region on HSA 9p suggests that DMRT1 represents an ancestral dosage-sensitive gene for vertebrate sex-determination. Z dosage may be crucial for male sexual differentiation/determination in birds.

Amino Acid Sequence↗
PubMed1999

Comparative mapping of mouse and rat chromosomes by fluorescence in situ hybridization.

Comparative fluorescence in situ hybridization mapping using DNA libraries from flow-sorted mouse chromosomes and region-specific mouse BAC clones on rat chromosomes reveals chromosomal homologies between mouse (Mus musculus, MMU) and rat (Rattus norvegicus, RNO). Each of the MMU 2, 3, 4, 6, 7, 9, 12, 14, 15, 16, 18, 19, and X chromosomes paints only a single rat chromosome or chromosome segment and, thus, the chromosomes are largely conserved between the two species. In contrast, the painting probes for MMU chromosomes 1, 5, 8, 10, 11, 13, and 17 produce split hybridization signals in the rat, disclosing evolutionary chromosome rearrangements. Comparative mapping data delineate several large linkage groups on RNO 1, 2, 4, 7, and 14 that are conserved in human but diverged in the mouse. On the other hand, there are linkage groups in the mouse, i.e., on MMU 1, 8, 10, and 11, that are disrupted in both rat and human. In addition, we have hybridized probes for Nap2, p57, Igf2, H19, and Sh3d2c from MMU 7 to RNO 1q and found the orientation of the imprinting gene cluster and Sh3d2c to be the same in mouse and rat. Hybridization of rat genomic DNA shows blocks of (rat-specific) repetitive sequences in the pericentromeric region of RNO chromosomes 3-5, 7-13, and 20; on the short arms of RNO chromosomes 3, 12, and 13; and on the entire Y chromosome.

Animals↗
PubMed1999

Classical and molecular cytogenetics of the pufferfish Tetraodon nigroviridis.

Because of its highly compact genome, the pufferfish has become an important animal model in genome research. Although the small chromosome size renders chromosome analysis difficult, we have established both classical and molecular cytogenetics in the freshwater pufferfish Tetraodon nigroviridis (TNI). The karyotype of T. nigroviridis consists of 2n = 42 biarmed chromosomes, in contrast to the known 2n = 44 chromosomes of the Japanese pufferfish Fugu rubripes (FRU). RBA banding can identify homologous chromosomes in both species. TNI 1 corresponds to two smaller FRU chromosomes, explaining the difference in chromosome number. TNI 2 is homologous to FRU 1. Fluorescence in-situ hybridization (FISH) allows one to map single-copy sequences, i.e. the Huntingtin gene, on chromosomes of the species of origin and also on chromosomes of the heterologous pufferfish species. Hybridization of total genomic DNA shows large blocks of (species-specific) repetitive sequences in the pericentromeric region of all TNI and FRU chromosomes. Hybridization with cloned human rDNA and classical silver staining reveal two large and actively transcribed rRNA gene clusters. Similar to the situation in mammals, the highly compact pufferfish genome is endowed with considerable amounts of localized repeat DNAs.

Animals↗
PubMed1998

Simian Y chromosomes: species-specific rearrangements of DAZ, RBM, and TSPY versus contiguity of PAR and SRY.

The three human male specific expressed gene families DAZ, RBM, and TSPY are known to be repetitively clustered in the Y-specific region of the human Y Chromosome (Chr). RBM and TSPY are Y-specifically conserved in simians, whereas DAZ cannot be detected on the Y chromosomes of New World monkeys. The proximity of SRY to the pseudoautosomal region (PAR) is highly conserved and thus most effectively stabilizes the pseudoautosomal boundary on the Y (PABY) in simians. In contrast, the non-recombining part of the Y Chrs, including DAZ, RBM, and TSPY, was exposed to species-specific amplifications, diversifications, and rearrangements. Evolutionary fast fixation of any of these variations was possible as long as they did not interfere with male fertility.

Animals↗
PubMed1997

Comparative mapping of Xp22 genes in hominoids--evolutionary linear instability of their Y homologues.

Several genes located within or proximal to the human PAR in Xp22 have homologues on the Y chromosome and escape, or partly escape, inactivation. To study the evolution of Xp22 genes and their Y homologues, we applied multicolour fluorescence in situ hybridization (FISH) to comparatively map DNA probes for the genes ANT3, XG, ARSD, ARSE (CDPX), PRK, STS, KAL and AMEL to prometaphase chromosomes of the human species and hominoid apes. We demonstrate that the genes residing proximal to the PAR have a highly conserved order on the higher primate X chromosomes but show considerable rearrangements on the Y chromosomes of hominoids. These rearrangements cannot be traced back to a simple model involving only a single or a few evolutionary events. The linear instability of the Y chromosomes gives some insight into the evolutionary isolation of large parts of the Y chromosomes and thus might reflect the isolated evolutionary history of the primate species over millions of years.

Animals↗