DOCSLIB.ORG

The Evolution of Human Chromosome 2

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Evolution of Human Chromosome 2 #Bio The evolution of human chromosome 2 Clare Sansom We humans like to think of ourselves as members of The reason for this difference can be seen from Downloaded from http://portlandpress.com/biochemist/article-pdf/37/5/40/3805/bio037050040.pdf by guest on 01 October 2021 (Birkbeck College, UK) a species like no other, but, as many of the articles in a straightforward examination of the human and this issue of The Biochemist explain, we are genetically chimpanzee chromosome sets using a light microscope. pretty ordinary. Our genomes contain no more DNA We have not lost any DNA relative to the chimpanzee and no more genes than an average vertebrate, and (or other great apes); rather, the distinct banding our chromosome number – as every high-school pattern of the chromosomes reveals that two of the ape biology student knows, 22 pairs of autosomes plus chromosomes must have fused to form one large one. XX or XY, making 46 in total – is just about in the This ‘new’ human chromosome is, in fact, the second middle of the range for mammals. Interestingly, the largest as viewed under a microscope, and it is therefore domestic dog (Canis lupus familiaris) has one of the named chromosome 2. The chimpanzee chromosomes largest mammalian genomes in terms of chromosome involved in the fusion have been named in derivative number, with 39 pairs. fashion as 2A and 2B. It is actually quite surprising that we have only 23 There are a number of free web-based resources pairs of chromosomes. In taxonomy, Homo sapiens is one available for browsing and comparing genomes from of seven species that make up the family Hominidae, or different species. One of the most widely used is the the great apes. Every other living species in this lineage, Ensembl database (http://www.ensembl.org), which is including our closest relatives, the chimpanzees Pan a joint project of the Sanger Institute and the European paniscus and Pan troglodytes, has 24 chromosome pairs. Bioinformatics Institute, both based on the Hinxton Less than 3% of our DNA sequence differs from that Genome Campus near Cambridge. This focuses on of the chimpanzee, so it might have been expected that vertebrate genomics, and the main part of the site we would share something as basic as our chromosome currently holds data on about 70 species ranging number as well. alphabetically from the aardvark to the zebrafish. Sequence data are released well before the genome of each species can be considered ‘finished’. If you go to Ensembl and click on the icon for the human genome, which can be found in the main species list and also, not surprisingly, as one of the ‘popular genomes’ on the site’s top page, you will be presented with a wide list of resources. To go to chromosome 2, you first select ‘view karyotype’, click on the second chromosome, and then select ‘Chromosome Summary’. Selecting ‘Synteny’ from the left-hand menu will initially produce a complex diagram showing that parts of this human chromosome have significant similarities with no fewer than ten chromosomes from the mouse. Changing species from mouse to chimpanzee while keeping the chromosome number the same reveals a much simpler picture: all of the short arm (2p) and a short segment of the long arm (2q) of human chromosome 2 is significantly similar to the chimpanzee chromosome named 2A, and the rest of the long arm is similar to www.ensembl.org/Homo_sapiens/Location/Synteny?db=core&r=2%3A206444782- the chromosome named 2B. Very short segments of 206544782&otherspecies=Pan_troglodytes the chromosome are marked as similar to three other 40 October 2015 © Biochemical Society #Bio Downloaded from http://portlandpress.com/biochemist/article-pdf/37/5/40/3805/bio037050040.pdf by guest on 01 October 2021 3D rendered illustration of X-chromosomes chimpanzee chromosomes, but, by comparison, these at about the point in evolutionary history when the are not particularly significant. lineages that led to humans and chimpanzees diverged, A detailed examination of the sequences of these i.e. about 6 million years ago. At that time, it seems, one chromosomes provides further evidence for an end-to- of the many species of ape roaming the forests of Africa end chromosome fusion. All eukaryotic chromosomes became split into two isolated populations. This led to have characteristic sequences at their centres (the genetic divergence between the two lineages, including centromeres) and ends (the telomeres). The DNA in the fusion that formed human chromosome 2, and from both of these regions is repetitive in sequence and codes that point onwards, the lineages could no longer breed; for few, if any, genes. An alignment of the human and one, or possibly two, new species had been created. chimpanzee chromosomes shows that the centromere of It would take genetic analysis to distinguish our human chromosome 2 lines up almost exactly with that direct ancestors, the first true hominins, from their of chimpanzee chromosome 2A. Furthermore, there proto-chimpanzee cousins. Over the subsequent is a segment of the long arm of human chromosome 2, 6 million years, the genomes of the two lineages close to its centromere, that has significant similarity to continued to diverge, with the human lineage chimpanzee telomeric DNA. The detailed sequence in gradually acquiring the features that distinguish it this region is exactly what you would expect to see if the from the chimpanzee, including its bipedal posture, two chimpanzee chromosomes had fused end-to-end. It small canine teeth and the large brains that allowed is interesting to note that one of the normal functions of us to develop the technology necessary to colonize the telomeres is to prevent just such an end-to-end fusion. and thrive in all of the major ecological niches that The exact mechanism through which these two this planet allows. So far, at least, our species can be chimpanzee chromosomes evaded their protective considered an evolutionary success. ■ telomeres to fuse is not yet completely understood, although we do know that no genes from the ends of This article draws on Matt Ridley’s excellent Genome: the chimpanzee chromosomes 2A and 2B appear to have Autobiography of a Species in 23 Chapters (Fourth Estate, been lost. We also know that it must have happened London, 2000; ISBN 978-1-857--02835-5). October 2015 © Biochemical Society 41.
Load more

Recommended publications
  • Combinatorial Genomic Data Refute the Human Chromosome 2 Evolutionary Fusion and Build a Model of Functional Design for Interstitial Telomeric Repeats
    The Proceedings of the International Conference on Creationism Volume 8 Print Reference: Pages 222-228 Article 32 2018 Combinatorial Genomic Data Refute the Human Chromosome 2 Evolutionary Fusion and Build a Model of Functional Design for Interstitial Telomeric Repeats Jeffrey P. Tomkins Institute for Creation Research Follow this and additional works at: https://digitalcommons.cedarville.edu/icc_proceedings Part of the Biology Commons, and the Genomics Commons DigitalCommons@Cedarville provides a publication platform for fully open access journals, which means that all articles are available on the Internet to all users immediately upon publication. However, the opinions and sentiments expressed by the authors of articles published in our journals do not necessarily indicate the endorsement or reflect the views of DigitalCommons@Cedarville, the Centennial Library, or Cedarville University and its employees. The authors are solely responsible for the content of their work. Please address questions to [email protected]. Browse the contents of this volume of The Proceedings of the International Conference on Creationism. Recommended Citation Tomkins, J.P. 2018. Combinatorial genomic data refute the human chromosome 2 evolutionary fusion and build a model of functional design for interstitial telomeric repeats. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 222–228. Pittsburgh, Pennsylvania: Creation Science Fellowship. Tomkins, J.P. 2018. Combinatorial genomic data refute the human chromosome 2 evolutionary fusion and build a model of functional design for interstitial telomeric repeats. In Proceedings of the Eighth International Conference on Creationism, ed. J.H. Whitmore, pp. 222–228. Pittsburgh, Pennsylvania: Creation Science Fellowship. COMBINATORIAL GENOMIC DATA REFUTE THE HUMAN CHROMOSOME 2 EVOLUTIONARY FUSION AND BUILD A MODEL OF FUNCTIONAL DESIGN FOR INTERSTITIAL TELOMERIC REPEATS Jeffrey P.
    [Show full text]
  • 1311.Full.Pdf
    Copyright © 2005 by the Genetics Society of America DOI: 10.1534/genetics.104.033167 Chromosome Loss Followed by Duplication Is the Major Mechanism of Spontaneous Mating-Type Locus Homozygosis in Candida albicans Wei Wu, Claude Pujol, Shawn R. Lockhart and David R. Soll1 Department of Biological Sciences, University of Iowa, Iowa City, Iowa 52242 Manuscript received July 7, 2004 Accepted for publication December 7, 2004 ABSTRACT Candida albicans, which is diploid, possesses a single mating-type (MTL) locus on chromosome 5, which is normally heterozygous (a/␣). To mate, C. albicans must undergo MTL homozygosis to a/a or ␣/␣. Three possible mechanisms may be used in this process, mitotic recombination, gene conversion, or loss of one chromosome 5 homolog, followed by duplication of the retained homolog. To distinguish among these mechanisms, 16 spontaneous a/a and ␣/␣ derivatives were cloned from four natural a/␣ strains, P37037, P37039, P75063, and P34048, grown on nutrient agar. Eighteen polymorphic (heterozygous) markers were identified on chromosome 5, 6 to the left and 12 to the right of the MTL locus. These markers were then analyzed in MTL-homozygous derivatives of the four natural a/␣ strains to distinguish among the three mechanisms of homozygosis. An analysis of polymorphisms on chromosomes 1, 2, and R excluded meiosis as a mechanism of MTL homozygosis. The results demonstrate that while mitotic recombination was the mechanism for homozygosis in one offspring, loss of one chromosome 5 homolog followed by duplication of the retained homolog was the mechanism in the remaining 15 offspring, indicating that the latter mechanism is the most common in the spontaneous generation of MTL homozy- gotes in natural strains of C.
    [Show full text]
  • Chromosome 2 Introduction the Genetic Length of Chromosome 2
    Chromosome 2 ©Chromosome Disorder Outreach Inc. (CDO) Technical genetic content provided by Dr. Iosif Lurie, M.D. Ph.D Medical Geneticist and CDO Medical Consultant/Advisor. Ideogram courtesy of the University of Washington Department of Pathology: ©1994 David Adler.hum_02.gif Introduction The genetic length of chromosome 2 spans ~237 Mb. It is ~8% of the whole human genetic material. The length of the short arm is ~89 Mb; the length of the long arm is 148 Mb. Chromosome 2 contains ~1500 genes. At least 200 of these genes are related to different kinds of genetic pathologies. Many of these genes are associated with structural defects of the organs, and others, to functional defects. The numerous structural abnormalities of chromosome 2 had already been reported before methods of molecular genetics gained wide usage. Currently there are ~1,500 reports on patients with varying structural abnormalities of this chromosome, including ~1,000 reports on patients with deletions. Deletions have been reported in at least 10–15 patients for each segment of chromosome 2. There are ten known syndromes caused by deletions of chromosome 2, including three syndromes related to deletions of the short arm (p). Some of these syndromes have been known for many years; others (del 2p15p16.1, del 2q23q24, and del 2q32) have been delineated only in the last couple of years. Deletions of Chromosome 2 Different types of chromosome 2 deletions have been described in numerous publications and may be subdivided into 3 groups: • Deletions that are “harmless” variants (usually familial) • Unique deletions that have not been categorized as a syndrome yet • Deletions that are considered a syndrome Deletions of 2p Deletion of 2p15p16.1 This syndrome, first described in 2007, is rare; only ten patienys have been described to date.
    [Show full text]
  • Detailed Genetic and Physical Map of the 3P Chromosome Region Surrounding the Familial Renal Cell Carcinoma Chromosome Translocation, T(3;8)(Pl4.2;Q24.1)1
    [CANCER RESEARCH 53. 3118-3124. July I. 1993] Detailed Genetic and Physical Map of the 3p Chromosome Region Surrounding the Familial Renal Cell Carcinoma Chromosome Translocation, t(3;8)(pl4.2;q24.1)1 Sal LaForgia,2 Jerzy Lasota, Parida Latif, Leslie Boghosian-Sell, Kumar Kastury, Masataka Olita, Teresa Druck, Lakshmi Atchison, Linda A. Cannizzaro, Gilad Barnea, Joseph Schlessinger, William Modi, Igor Kuzmin, Kaiman Tory, Berton Zbar, Carlo M. Croce, Michael Lerman, and Kay Huebner3 Jefferson Cancer Institute. Thomas Jefferson Medical College. Philadelphia, Pennsylvania 19107 (S. L. J. L. L B-S.. K. K.. M. O.. T. D.. L A. C.. C. M. C.. K. H.I: Laboratory of Immunobiology. National Cancer Institute. Frederick Cancer Research and Development Center. Frederick. Maryland 21701 (F. L, l. K.. K. T.. B. Z.. M. L): Biological Carcinogenesis and Development Program. Program Resources Inc./Dyn Corp.. Frederick Cancer Research and Development Center. Frederick. Maryland 21701 1W. M.Õ: Chestnut Hill College. Philadelphia. Pennsylvania 19118 (L A.): and Department oj Pharmacology. New York University. New York. New York 10012 (G. B., J. S.I ABSTRACT location of the critical 3p region(s) harboring the target gene(s) had been hampered by the paucity of well-localized, widely available Extensive studies of loss of heterozygosity of 3p markers in renal cell molecular probes. Recently, efforts to isolate and localize large num carcinomas (RCCs) have established that there are at least three regions bers of 3p molecular probes have been undertaken (25-28). As the critical in kidney tumorigenesis, one most likely coincident with the von Hippel-Lindau gene at 3p25.3, one in 3p21 which may also be critical in probe density on 3p increased, in parallel with recent LOH studies, it small cell lung carcinomas, and one in 3pl3-pl4.2, a region which includes became clear that multiple independent loci on 3p were involved the 3p chromosome translocation break of familial RCC with the t(3;8)- (summarized in Refs.
    [Show full text]
  • Down's Syndrome Phenotype and Autosomal Gene Inactivation in a Child with Presumed
    J Med Genet: first published as 10.1136/jmg.19.2.144 on 1 April 1982. Downloaded from 144 Case reports Down's syndrome phenotype and Case report autosomal gene inactivation in a The proband, a 3 2-year-old white female, was referred for evaluation of developmental delay and child with presumed (X;21) de novo dysmorphic features. She was the 1790 g,. 39 week translocation gestation product of a gravida 1, para 0, 15-year-old female. The pregnancy was complicated with SUMMARY A 32-year-old female with clinical recurrent urinary tract infections. The mother used features of Down's syndrome was found to have alcohol and tobacco in small quantities during the extra chromosome material on the long arm of pregnancy. The labour lasted ten hours and the one of the X chromosomes, 46,XXq+. The delivery was vaginal with vertex presentation. The parental karyotypes were normal. In the light baby breathed and cried spontaneously. Her of the clinical features of the proband and the immediate neonatal course was uneventful, but her subsequent weight gain was poor. She had several banding characteristics of the extra chromosome admissions to hospital for repeated diarrhoea, otitis material, the patient was thought to have a de media, and pneumonia. She had two 'febrile' seizures novo (X;21) translocation. The results of late for which she was placed on phenobarbital. Her replication studies with BUdR and enzyme development was markedly delayed. She smiled at superoxide dismutase (SOD) assays in the 4 months, turned over at 7 months, walked at 18 proband suggest that: (1) the presumed (X;21) months, and was not yet toilet trained.
    [Show full text]
  • Investigation of Differentially Expressed Genes in Nasopharyngeal Carcinoma by Integrated Bioinformatics Analysis
    916 ONCOLOGY LETTERS 18: 916-926, 2019 Investigation of differentially expressed genes in nasopharyngeal carcinoma by integrated bioinformatics analysis ZhENNING ZOU1*, SIYUAN GAN1*, ShUGUANG LIU2, RUjIA LI1 and jIAN hUANG1 1Department of Pathology, Guangdong Medical University, Zhanjiang, Guangdong 524023; 2Department of Pathology, The Eighth Affiliated hospital of Sun Yat‑sen University, Shenzhen, Guangdong 518033, P.R. China Received October 9, 2018; Accepted April 10, 2019 DOI: 10.3892/ol.2019.10382 Abstract. Nasopharyngeal carcinoma (NPC) is a common topoisomerase 2α and TPX2 microtubule nucleation factor), malignancy of the head and neck. The aim of the present study 8 modules, and 14 TFs were identified. Modules analysis was to conduct an integrated bioinformatics analysis of differ- revealed that cyclin-dependent kinase 1 and exportin 1 were entially expressed genes (DEGs) and to explore the molecular involved in the pathway of Epstein‑Barr virus infection. In mechanisms of NPC. Two profiling datasets, GSE12452 and summary, the hub genes, key modules and TFs identified in GSE34573, were downloaded from the Gene Expression this study may promote our understanding of the pathogenesis Omnibus database and included 44 NPC specimens and of NPC and require further in-depth investigation. 13 normal nasopharyngeal tissues. R software was used to identify the DEGs between NPC and normal nasopharyngeal Introduction tissues. Distributions of DEGs in chromosomes were explored based on the annotation file and the CYTOBAND database Nasopharyngeal carcinoma (NPC) is a common malignancy of DAVID. Gene ontology (GO) and Kyoto Encyclopedia of occurring in the head and neck. It is prevalent in the eastern Genes and Genomes (KEGG) pathway enrichment analysis and southeastern parts of Asia, especially in southern China, were applied.
    [Show full text]
  • Rapid Molecular Assays to Study Human Centromere Genomics
    Downloaded from genome.cshlp.org on September 26, 2021 - Published by Cold Spring Harbor Laboratory Press Method Rapid molecular assays to study human centromere genomics Rafael Contreras-Galindo,1 Sabrina Fischer,1,2 Anjan K. Saha,1,3,4 John D. Lundy,1 Patrick W. Cervantes,1 Mohamad Mourad,1 Claire Wang,1 Brian Qian,1 Manhong Dai,5 Fan Meng,5,6 Arul Chinnaiyan,7,8 Gilbert S. Omenn,1,9,10 Mark H. Kaplan,1 and David M. Markovitz1,4,11,12 1Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, USA; 2Laboratory of Molecular Virology, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Montevideo, Uruguay 11400; 3Medical Scientist Training Program, University of Michigan, Ann Arbor, Michigan 48109, USA; 4Program in Cancer Biology, University of Michigan, Ann Arbor, Michigan 48109, USA; 5Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan 48109, USA; 6Department of Psychiatry, University of Michigan, Ann Arbor, Michigan 48109, USA; 7Michigan Center for Translational Pathology and Comprehensive Cancer Center, University of Michigan Medical School, Ann Arbor, Michigan 48109, USA; 8Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA; 9Department of Human Genetics, 10Departments of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, USA; 11Program in Immunology, University of Michigan, Ann Arbor, Michigan 48109, USA; 12Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan 48109, USA The centromere is the structural unit responsible for the faithful segregation of chromosomes. Although regulation of cen- tromeric function by epigenetic factors has been well-studied, the contributions of the underlying DNA sequences have been much less well defined, and existing methodologies for studying centromere genomics in biology are laborious.
    [Show full text]
  • Evolution of Genetic and Genomic Features Unique to the Human Lineage
    REVIEWS Evolution of genetic and genomic features unique to the human lineage Majesta O’Bleness1, Veronica B. Searles1, Ajit Varki2,3,4, Pascal Gagneux3,4 and James M. Sikela1,4 Abstract | Given the unprecedented tools that are now available for rapidly comparing genomes, the identification and study of genetic and genomic changes that are unique to our species have accelerated, and we are entering a golden age of human evolutionary genomics. Here we provide an overview of these efforts, highlighting important recent discoveries, examples of the different types of human-specific genomic and genetic changes identified, and salient trends, such as the localization of evolutionary adaptive changes to complex loci that are highly enriched for disease associations. Finally, we discuss the remaining challenges, such as the incomplete nature of current genome sequence assemblies and difficulties in linking human-specific genomic changes to human-specific phenotypic traits. 1,2 Accelerated evolution Many phenotypic traits that are unique to the human lin- expression of human regulatory regions in mice , are More nucleotide or copy eage are likely to have resulted from selective pressures allowing for evolutionary hypotheses to be tested in number changes in a particular on our genome and the unique demographic history ways that were previously not possible. Work in this region or gene than would be since our divergence from the Pan lineage approximately field has substantially advanced in recent years: the expected from background (BOX 1) rates of mutation over time 6 million years ago . A fundamental question that number of gene‑to‑phenotype candidates has more (for example, in cytochrome c relates to the origin of our species is which genomic than doubled since the topic was last covered in two oxidase subunit Va (COX5A)).
    [Show full text]
  • Duplications of 2P FTNW
    Duplications of 2p rarechromo.org She made me re-evaluate my life. Nearly losing her made me realise how important my kids and family are. I stopped work. I do not want to miss a minute of my kids’ lives. He has a lovely smile and has taught us not to be selfish and to count our blessings. Duplications of chromosome 2p A duplication of 2p means that the cells of the body have extra genetic material from one of their 46 chromosomes – chromosome 2. For healthy development, chromosomes should contain just the right amount of genetic material (DNA) – not too much and not too little. Like most other chromosome disorders, having extra material from chromosome 2 can increase the risk of birth defects, developmental delay and learning difficulties. But the problems vary and depend very much on what extra genetic material is present and how much. Chromosomes and genes Chromosomes are structures found in the nucleus of the body’s cells. They contain thousands of genes which themselves contain all the genetic information the body needs to develop, grow and function. Chromosomes (and genes) usually come in pairs, with one chromosome from each pair inherited from each parent. Humans have 23 pairs of chromosomes, giving a total of 46 individual chromosomes. Of these 46 chromosomes, two are the sex chromosomes that determine gender. Females have two X chromosomes and males have one X chromosome and one Y chromosome. The remaining 44 chromosomes are grouped in 22 pairs, numbered 1 to 22 approximately from the largest to the smallest, so chromosome 2 is the largest chromosome but one.
    [Show full text]
  • Diatom Centromeres Suggest a Mechanism for Nuclear DNA Acquisition
    Diatom centromeres suggest a mechanism for nuclear PNAS PLUS DNA acquisition Rachel E. Dinera,b, Chari M. Noddingsc, Nathan C. Lianc, Anthony K. Kangc, Jeffrey B. McQuaida,b, Jelena Jablanovicb, Josh L. Espinozab, Ngocquynh A. Nguyenc, Miguel A. Anzelmatti Jr.b, Jakob Janssonc, Vincent A. Bielinskic, Bogumil J. Karasc,1, Christopher L. Dupontb, Andrew E. Allena,b, and Philip D. Weymanc,2 aIntegrative Oceanography Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037; bMicrobial and Environmental Genomics Group, J. Craig Venter Institute, La Jolla, CA 92037; and cSynthetic Biology and Bioenergy Group, J. Craig Venter Institute, La Jolla, CA 92037 Edited by James A. Birchler, Division of Biological Sciences, University of Missouri, Columbia, MO, and approved June 13, 2017 (received for review January 17, 2017) Centromeres are essential for cell division and growth in all eukary- transposons, which can vary substantially in copy number and otes, and knowledge of their sequence and structure guides the organization (16). A common feature of centromeric DNA in many development of artificial chromosomes for functional cellular biol- eukaryotes is low-GC content. Centromeres of Schizosaccharomyces ogy studies. Centromeric proteins are conserved among eukaryotes; pombe and other yeast species feature an unconserved core of AT- however, centromeric DNA sequences are highly variable. We rich DNA sequence often surrounded by inverted repeats (17–20). combined forward and reverse genetic approaches with chromatin The centromeres of the protist Plasmodium have no apparent se- immunoprecipitation to identify centromeres of the model diatom quence similarity besides being 2–4-kb regions of extremely low-GC Phaeodactylum tricornutum .
    [Show full text]
  • Origin of Human Chromosome 2: an Ancestral Telomere-Telomere Fusion J
    Proc. Nadl. Acad. Sci. USA Vol. 88, pp. 9051-9055, October 1991 Genetics Origin of human chromosome 2: An ancestral telomere-telomere fusion J. W. IJDO*t, A. BALDINIt§, D. C. WARDt, S. T. REEDERS**, AND R. A. WELLS*¶ *Howard Hughes Medical Institute and tDepartment of Genetics, Yale University School of Medicine, New Haven, CT 06510 Communicated by Alan Garen, July 8, 1991 ABSTRACT We have identified two allelic genomic a human genomic 300-base-pair (bp) Alu I fragment present cosmids from human chromosome 2, c8.1 and c29B, each at the subtelomeric regions offive different chromosomes, as containing two inverted arrays of the vertebrate telomeric well as at a single nonterminal locus at 2q13, described repeat in a head-to-head arrangement, 5'(TTAGGG),,- elsewhere (8). Sixty positives were screened subsequently (CCCTAA),,3'. Sequences fln g this telomeric repeat are with a (TTAGGG)" probe (n varies between 10 and 1000). characteristic of present-day human pretelomeres. BAL-31 Fifteen cosmids hybridized to both pSC4 and (TTAGGG),. nuclease experiments with yeast artificial chromosome clones Cosmid Mapping to Chromosome 2. Probe pSC4 detects of human telomeres and fluorescence in situ hybridization five different size fragments on a Pst I digest of total human reveal that sequences flanking these inverted repeats hybridize DNA representing the different chromosomal loci. Of these, both to band 2q13 and to different, but overlapping, subsets of a 2.5-kb Pst I fragment was assigned to chromosome 2 by human chromosome ends. We conclude that the locus cloned in means ofhybridization ofpSC4 to 34 somatic cell hybrid lines cosmids c8.1 and c29B is the relic of an ancient telomere- (obtained, in part, from BIOS, New Haven, CT).
    [Show full text]
  • Mapping of Transforming Growth Factor a Gene on Human Chromosome 2 Close to the Breakpoint of the Burkitt's Lymphoma T(2;8) Variant Translocation1
    (CANCER RESEARCH 45, 5593-5597, November 1985] Mapping of Transforming Growth Factor a Gene on Human Chromosome 2 Close to the Breakpoint of the Burkitt's Lymphoma t(2;8) Variant Translocation1 Jane E. Brissenden, Rik Derynck, and Uta Francke Department of Human Genetics, Yale University School of Medicine, New Haven, Connecticut 06510 [J. E. B., U. F.], and Department of Molecular Biology, Genentech, Inc., South San Francisco, California 94080 [R. D.] ABSTRACT or EGF to induce transformation of normal rabbit kidney indicator cells (8, 9) and do not compete with EGF for binding to EGF Transforming growth factors (TGFs) are defined as biologically receptors although they do induce an increase of EGF receptor active polypeptides which reversibly confer the transformed phe- numbers on normal rabbit kidney cells in culture (11). notype onto untransformed cultured cells. TGF-a shows se TGFs-a have been suggested to play a physiological role in quence homology with epidermal growth factor and competes embryonic development (12), and many observations have linked with epidermal growth factor for binding to the epidermal growth their secretion to the malignant transformation of cells. For factor receptor, stimulating the phosphorylation of the receptor. example, cells transformed with a temperature sensitive Kirsten TGF-a is secreted by many transformed cells and may be murine sarcoma virus secrete TGF-a only when phenotypic involved in embryonic development. transformation occurs at the permissive temperature (13). Intro A cloned human TGF-a gene was used to map the locus for duction of the DNA segment coding for middle T-antigen of the TGF-a precursor to the short arm of human chromosome 2, polyoma virus into cells is sufficient to induce both a transformed region 2p11-»2p13, by Southern blotting techniques with DNA phenotype and TGF-a secretion (14).
    [Show full text]