What Are Chromosome Rearrangements?

Chromosome rearrangements are structural changes that alter the normal configuration of chromosomes. These changes can involve large segments of DNA — from thousands to millions of base pairs — and can occur spontaneously, be inherited, or result from exposure to mutagens (like radiation or chemicals).

Common Types of Rearrangements:

1. Deletions – Loss of a chromosome segment

2. Duplications – Repetition of a segment

3. Inversions – A segment breaks off, flips, and reattaches

4. Translocations – Segments exchange places between non-homologous chromosomes

5. Insertions – A segment is inserted into another part of the genome

These changes can disrupt genes directly or affect gene regulation, leading to disease.

How Do Chromosome Rearrangements Cause Disease?

The impact of a rearrangement depends on which genes are involved, how much DNA is affected, and when the rearrangement occurs (in development vs. adulthood). Here are some key mechanisms:

• Gene disruption: Breaking a gene can lead to loss of function or the creation of a non-functional protein.

• Gene fusion: Joining parts of two genes may form a novel hybrid gene with new functions (common in cancer).

• Dosage effects: Extra or missing gene copies can disturb the balance of gene expression.

• Position effects: Moving a gene to a new regulatory environment may silence or over-activate it.

Chromosome Rearrangements in Human Disease

1. Developmental Disorders

• Cri-du-chat syndrome: Caused by a deletion on chromosome 5p. Affected infants often have a high-pitched cry and intellectual disability.

• Williams syndrome: Results from a microdeletion on chromosome 7q, affecting genes related to cardiovascular and cognitive function.

2. Cancer

Cancer is perhaps the most striking example of disease caused by chromosome rearrangements.

• Chronic Myeloid Leukemia (CML): Caused by a translocation between chromosomes 9 and 22, forming the Philadelphia chromosome. This creates the BCR-ABL fusion gene, which drives uncontrolled cell growth.

• Burkitt lymphoma: Involves translocation of the MYC gene, leading to excessive cell division.

• Ewing sarcoma: A fusion of EWSR1 and FLI1 genes through translocation promotes tumor development.

3. Infertility and Miscarriages

Balanced rearrangements (like inversions or translocations) in carriers may not cause disease directly but can result in:

• Recurrent miscarriages

• Infertility

• Birth defects in offspring

Detecting Rearrangements

Thanks to modern genomics, chromosome rearrangements can now be detected with high precision using:

• Karyotyping – Classic method for detecting large rearrangements

• FISH (Fluorescence In Situ Hybridization) – Uses fluorescent probes to target specific DNA sequences

• Array CGH (Comparative Genomic Hybridization) – Detects copy number changes across the genome

• Whole Genome Sequencing (WGS) – Identifies even small or complex rearrangements at base-pair resolution

Looking Forward: The Future of Chromosome Medicine

Understanding chromosome rearrangements is now central to:

• Personalized medicine

• Genetic counseling

• Targeted therapies, especially in cancer (e.g., tyrosine kinase inhibitors for BCR-ABL fusion)

With the rise of long-read sequencing and single-cell genomics, even previously “invisible” rearrangements are being uncovered, offering new insights into both rare diseases and common conditions.

Final Thoughts

Chromosome rearrangements remind us that genetics isn't just about which genes we have — but where they are, how they're arranged, and when they're active. As our tools grow sharper, so does our ability to diagnose, understand, and treat diseases rooted in genomic architecture.

In a way, the genome is like a book not just defined by its words, but also by how the chapters are ordered. Rearranging them can create a new story — sometimes harmful, sometimes insightful — and understanding these changes is key to writing a healthier future.

To address the challenges of describing and estimating virodiversity, a team of investigators from Center for Infection and Immunity (CII) and EcoHealth Alliance began in jungles of Bangladesh - home to the flying fox.

Reference:

http://economictimes.indiatimes.com/news/news-by-industry/et-cetera/mammals-harbour-at-least-320000-new-viruses/articleshow/22253268.cms

http://www.bbc.co.uk/news/science-environment-23932400

Applications in plain paper are invited for the posts of (1) Traineeship (2 Nos.) and (2) Studentship – (2 Nos.) in the DBT funded-Bioinformatics Infrastructure Facility (BIF), Nagaland University, Lumami-798627, Nagaland. Details are given below. Interested candidates may submit the application along with self attested copies of certificates in support of the candidature to Prof. Chitta Ranjan Deb, Coordinator or Dr. L. N. Kakati, Deputy Coordinator, BIF Centre, Nagaland University, Lumami-798627, Nagaland on or before 15th January 2015.

The scanned application with relevant documents may be sent by email attachment to bifnulumami@gmail.com. Shortlisted candidates will be informed by email if called for interview. No TA/DA is admissible for attending the interview.

Traineeship (Two nos.)

Post Graduate degree in any branch of Life Sciences from UGC recognized Universities

Knowledge of computers and bioinformatics

Rs.8000/- p.m. fixed.

6 months

Studentship (Two nos.)

Pursuing Post Graduate degree in any branch of Life Sciences from UGC recognized Universities

Knowledge of computers and bioinformatics

Rs.8000/- p.m. fixed.

6 months

Terms and Conditions:

i) Applicants need to produce all original documents if call for interview.
ii) The posts are purely temporary and the appointment does not confer any entitlement or right over the job and will not be considered as formal service.
iii) No TA & DA will be paid for appearing in the walk-in-interview.
iv) The stipend/salary amount is subject to the sanction of DBT, New Delhi.

Advertisement: http://www.nagauniv.org.in/files/BIF%20Advt.pdf

Now a day, geneticists have developed a language of their own. They are pouring lots of money and energy to read the entire genomic text and understand the gods own code ATGC. It is somewhat fascinating, not only for geneticist but also for non-biologist to know that there are several conserved blocks in genome which remain conserved over hundreds of millions of years. There have been several researches on conserved blocks and non-conserved regions to understand the mechanism and importance of all these regions (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675965/). The finding indicates conservation and rearrangements of certain evolutionary important genes play an important role in evolution/adaptive changes (http://www.nature.com/nature/journal/v491/n7424/abs/nature11622.html https://academic.oup.com/gbe/article/8/8/2442/2198198/Novel-Insights-into-Chromosome-Evolution-in-Birds , http://science.sciencemag.org/content/346/6215/1311).

But the puzzle remains open, how to correctly define the synteny (presence of two or more genes on the same chromosome) and conserved synteny (presence of two or more genes on chromosome of each of the two species) on several genomes.

Figure: Image generated with Evolution Highway (EH) tool http://eh-demo.ncsa.illinois.edu/ 

Keeping the new approach to define conserved synteny in mind there have been various algorithms developed to identify the conserved homologous synteny blocks (HSB) amongst species. Some of them which were commonly used for synteny detections are:

SyntenyTracker ( http://www-app.igb.uiuc.edu/labs/lewin/donthu/Synteny_assign/html/),

SyntenyTracker was shown to be an efficient and accurate automated tool for defining HSBs using datasets that may contain minor errors resulting from limitations in map construction methodologies.

CoGe (http://genomevolution.org/CoGe/SynFind.pl )

Satsuma (http://evomics.org/learning/genomics/satsuma/)

Cinteny (http://cinteny.cchmc.org/) ,

Cinteny server can be used for finding regions syntenic across multiple genomes and measuring the extent of genome rearrangement using reversal distance as a measure.

OrthoCluster (http://krono.act.uji.es/noticias/orthocluster-a-new-tool-for-mining-syntenic-blocks)

A new tool for mining syntenic blocks in comparative genomics

SynMap (http://genomevolution.org/wiki/index.php/SynMap),

SyMAP (http://www.symapdb.org/)

SyMAP (Synteny Mapping and Analysis Program) v4.0 is an automated system for identifying and displaying genome synteny alignments. The genomes may be represented by sequenced chromosomes (pseudomolecules), by draft sequence contigs, or by FPC physical maps (with BAC-end or marker sequence).

http://genomevolution.org/CoGe/SynMap.pl

RegionMiner (http://www.genomatix.de/online_help/help_regionminer/orthologous.html)

SyntenyMiner is being developed as an application to visualize and interrogate comparisons among multiple complete genome sequences. http://syntenyminer.sourceforge.net/

AutoGRAPH ( http://autograph.genouest.org/),

AutoGRAPH is an integrated web server for multi-species comparative genomic analysis. It is designed for constructing and visualizing synteny maps between two or three species, determination and display of macrosynteny and microsynteny relationships among species, and for highlighting evolutionary breakpoints.

SynChro(http://www.lgm.upmc.fr/CHROnicle/SynChro.html)

SynChro is a tool designed to define conserved synteny blocks. It reconstructs synteny blocks between pairwise comparison of multiple genomes. The reconstructed synteny blocks may overlap each other, be included in one another or duplicated due to micro-rearrangements.

SyntenyView ( http://www.cbs.dtu.dk/dtucourse/cookbooks/nikob/exercises/gf1_output_5.html),

Ensembl 'SyntenyView' shows conservation of large-scale gene order between species pairs. A brief summary of the calculation method appears at the bottom of this help page.  The left of a 'SyntenyView' page displays a diagram of chromosomes with blocks of conserved synteny. The right of a page shows homology matches between individual genes within syntenic blocks.

SynBrowse ( http://www.synbrowse.org/),

SynBrowse (Synteny Browser) is a generic sequence comparison tool for visualizing genome alignments both within and between species. It is intended to help scientists study and analyze synteny, homologous genes and other conserved elements between sequences. This software is useful in studying genome duplication and evolution. It can also aid in identifying uncharacterized genes, putative regulatory elements and novel structural features of study species by comparing to a well annotated reference sequence, thus enabling genome curators to refine and edit annotations of species that have incomplete genome annotations.

Sibelia (http://arxiv.org/abs/1307.7941).

A comparative genomic tool: It assists biologists in analysing the genomic variations that correlate with pathogens, or the genomic changes that help microorganisms adapt in different environments. Sibelia will also be helpful for the evolutionary and genome rearrangement studies for multiple strains of microorganisms.

GSV (http://cas-bioinfo.cas.unt.edu/gsv/homepage.php)

Genome Synteny Viewer allows users to upload files which contain synteny regions between two or more genomes and interactively visualize the synteny between them. GSV also allows users to upload annotation files to visualize annotated regions in addition to synteny regions.

MicroSyn (http://www.lgm.upmc.fr/CHROnicle/SynChro.html)

MicroSyn software as a means of detecting microsynteny in adjacent genomic regions surrounding genes in gene families. MicroSyn searches for conserved, flanking colinear homologous gene pairs between two genomic fragments to determine the relationship between two members in a gene family.

SynOrth (http://synorth.genereg.net/)

Synorth [s n ôrth], named in combination of "synteny" and "ortholog", is designed for the study of evolutionary changes of genomic regulatory blocks (GRBs) in vertebrate genomes, and especially the changes following the whole-genome duplication in teleost fish, by tracing the ortholog genes gain and loss in ancient synteny blocks.

SyDiG (http://www.ncbi.nlm.nih.gov/pubmed/21441096)

Uncovering Synteny in Distant Genomes.

MapSynteny  (http://www.automatizacionysistemas.com/download.html)

MapSynteny is a macro in MS Excel® able to create images to show the relationship between genetic maps and large sequences (scaffolds, chromosomes, BACs, etc.). Based on tab – delimited BLAST results and some formulas, a suitable image of syntenic relationships or physical mapping can be obtained. http://www.automatizacionysistemas.com/Poster_MapSynteny.pdf

One of the best synteny tutorial for beginer @ http://www.nature.com/scitable/topicpage/synteny-inferring-ancestral-genomes-44022

Reference:

http://www.nature.com/scitable/topicpage/synteny-inferring-ancestral-genomes-44022

http://www.nature.com/nature/journal/v491/n7424/full/nature11622.html

http://en.wikipedia.org/wiki/Synteny

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2675965/

Qualifications Essential:
Doctoral degree in Bio-informatics/ Biotechnology/Molecular Biology and Biotechnology/Life Sciences/ Computer Sciences with specialization in Bio-informatics including relevant basic sciences with 8 years’ experience in the relevant subject as Scientist/Lecturer or in an equivalent position in the Pay Band- 3 of 15600-39100 with Grade Pay of 5400/6000/7000/8000 having made contribution to research/teachin/extension education as evidenced by published work/innovations and impact.

OR

Doctoral degree in the above subject(s) including relevant basic sciences with minimum 8 years’ experience of high quality post-doctoral research in an institution/organization as evidenced by at least 6 publications in journals with NAAS rating of 7.5 or above.

Desirable:
(i) Specialization and experience: Knowledge of software development and its application in crop bioinformatics, experience in handling ‘omies’data.
(ii) Teaching experience in relevant subject

The Secretary, Agricultural Scientists Recruitment Board, Indian Council of Agricultural Research Krishi Anusandhan Bhavan-I, Pusa New Delhi –110 012, India

Detailed eligibility criteria with how to apply information can be had at:
http://www.indiastudychannel.com/jobs/333467-Indian-Council-of-Agricultural-Research-looking-for-Assistant-Director-General.aspx

More at http://asrb.org.in/administrator/uploads_dir/1418978057english.pdf

The developers and expert trainers are the authors of several popular R packages, including ggplot2, plyr, lubridate, and others.

More at http://www.rstudio.com/

http://www.rstudio.com/products/RStudio/

Address of the bookmark: http://www.rstudio.com/

Following are the list of journals publishing pint-sized articles go by various names, such as genome reports, genome announcements, genome notes or genome letters, but will be referred to here broadly as genome reports.

1. Genome Announcements, American Society for Microbiology, Genome announcement, Impact factor 1.3,  A 500-word report stating that the genome of a particular organism (prokaryote, eukaryote or virus) has been sequenced and providing a citable record of the corresponding GenBank submission. Must include abstract but no text headings can be used except for ‘Acknowledgments’ and ‘References’. Cannot include figures, tables or supplemental material to present data or analysis.

Link: https://mra.asm.org/

2. Genome Biology and Evolution, Oxford University Press, Genome report, Impact factor 4.2, Focused 1500-word papers (up to six tables or figures) that publish the main evolutionary message of new genome sequences as they become submitted to GenBank. May also contain specifically focused comparative analyses of previously published genomes that contain a substantial and novel insight of broadest evolutionary significance.

Link: https://academic.oup.com/gbe

3. Journal of Biotechnology, Elsevier, Genome announcement, Impact factor 2.9, A 500-word report announcing the availability of the completely annotated genome sequence of a biotechnologically relevant organism in the corresponding database (for eukaryotes, advanced draft genomes will also be considered). Articles can contain an Abstract, a brief report on the organism and its biotechnological relevance, a table summarizing the genome features, References and an Acknowledgement. Figures are generally not allowed.

Link: https://www.journals.elsevier.com/journal-of-biotechnology

4. Journal of Genomics, Ivyspring, Genome note, Impact factor N/A, A 1000-word report (10 reference limit; conclusions not permitted) describing novel data sets from high-throughput analysis of genotypes, phenotypes, gene expression, metabolomes, proteomes or genome assemblies.Standard metrics for data quality and the experimental design must be clearly reported.

Link: http://www.jgenomics.com/

5. Memórias do Instituto, Oswaldo Cruz Oswaldo Cruz Foundation, Genome announcement and highlight, Impact factor 1.6, Dedicated to publishing new genome information from eukaryote parasites, virus, bacteria and their respective vectors, as well as re-sequencing or comparative genome analyses. Should occupy no more than three printed pages including figures and/or tables.

Link: http://memorias.ioc.fiocruz.br/

6. Molecular Ecology Resources, Wiley, Genomic resources note,  Impact factor 3.7, Short notes on newly assembled and annotated transcriptomes, genome fractions or whole genomes, and/or a library of SNP/SSR markers.Authors submit a short manuscript describing how the resource was developed and where the data can be accessed. Do not appear in journal as individual papers but are instead published as part of a summary article.

Link: https://onlinelibrary.wiley.com/journal/17550998

7. Standards in Genomic Science, BioMed Central (Springer), Short genome report, Impact factor 3.2, Short (∼500-word) article on newly sequenced genome. Article format must follow guidelines and template (available from journal Web site) put forward by the SGS. Any manuscripts not using template or that are missing key figures, tables and/or references (as per the guidelines) will be returned to authors. Rationale of the content model is to provide information that is consistently and uniformly presented for rapid and easy consumption by both human and machine readers. 

Link: https://standardsingenomics.biomedcentral.com/

8. 3biotech, Springer, Short genome report, Impact factor 1.3, Short (∼500-word) article on newly sequenced genome. Article format must follow guidelines (available from journal Web site).  Genome of a particular organism (prokaryote, eukaryote or virus) has been sequenced and providing a citable record of the corresponding GenBank submission.

Link: https://link.springer.com/journal/13205

Website: www.actrec.gov.in; Ph: 27405000

No. ACTREC/Advt./ 66 /2014 23rd December, 2014
Research Associate

International Cancer Genome Consortium (ICGC) - India Project (IRB Project No. 3 A/c. No. 2408)

Dr. Rajiv Sarin

Duration of the Project: One year Extendable up to Three years.

Consolidated Salary: Rs. 42,000/- p.m.

Application last date: 8th January, 2015.

Interview Date & Time: 21st January, 2015, at 11.00 a.m.

Venue: Conference Room, 3rd floor, Khanolkar Shodhika, ACTREC.

Essential Qualifications and Experience:

Ph.D (any branch of Life Sciences)

The candidate must have at least one year experience after Ph.D., preferably in Genomics and Molecular Biology.

Candidates fulfilling these requirements should pre register themselves by sending their application in the prescribed format with recent CV and contact details of 2 referees by e-mail to icgc@actrec.gov.in latest 8th January, 2015 by 10.00 a.m.

Candidates shortlisted for the interview will be intimated by email on or before 9th January, 2015.

The interviews would be held on 21st January 2015 and will be only for the pre registered candidates who have been shortlisted.
No T.A./D.A. will be admissible for attending the interview.

At the time of Interview the candidate should bring original certificates along with CV with contact details of 2 referees and submit the photocopies (attested) of the certificates, with a recent passport size photograph.

Advertisement: www.actrec.gov.in/data%20files/2014/Walk-in-Research-Fellow-26-12-14.doc