Chromosomes in Biological News

Double success for Instituto Gulbenkian de Ciencia scientists working on chromosome segregation

... of proteins that ensures accurate segregation of chromosomes during cell division - a fundamental step to ... with reduced risk of cancer. When segregating, chromosomes attach and move along proteins tracks (the ... the centromere did not assemble correctly and chromosomes segregated abnormally, leading to situations ...

New, less invasive genetic test greatly improves pregnancy rates in older women with poor prognosis

... Amsterdam, The Netherlands: A new test examining chromosomes in human eggs a few hours after fertilisation can ... Hybridisation (CGH) technique to count the chromosomes in each egg. Unlike conventional screening ... (FISH) method, which allows less than half of the chromosomes of an embryonic cell to be examined, CGH enables ...

Is this the beginning of the end of plant breeding?

... cell's DNA. Once replication has occurred, the chromosomes condense into tightly bound structures, and in ... copy of the chromosome. The double-chromatid chromosomes line up along the centre of the cell. In mitosis, ... first lining up is of homologous chromosomesall chromosomes in an adult cell have a partner, members of the ...

Slicing chromosomes leads to new insights into cell division

... ultrafast laser pulses to slice off pieces of chromosomes and observe how the chromosomes behave, biomedical engineers at the University of ... through mitosis, during which the DNA-containing chromosomes separate between the resulting daughter cells. ...

Yeast missing sex genes undergo unexpected sexual reproduction

... the process of sexual cell division that reduces chromosomes to half their number in the progeny? By ... two-thirds have the classic 50:50 division of chromosomes from the split parent cell, but a third of them ... eggs or fusion products may be aneuploid, with chromosomes from mother and father not paired exactly one to ...

The story of X -- evolution of a sex chromosome

... But in life forms that do set aside a pair of chromosomes to specify sex from fruit flies to mammals and some plants the two X chromosomes inherited by females look nearly identical to the ... melanogaster, a laboratory favorite, the sex chromosomes arose independently about 100 million years ago. ...

Evolutionary origin of bacterial chromosomes revealed

... bacteria suggests a general model for how second chromosomes are formed in bacteria.* Agrobacteria are ... that span single chromosomes, multiple chromosomes and circular DNA molecules (plasmids) of various ... family in that all of its members have either two chromosomes or one chromosome and very large plasmids. Until ...

Biologists discover link between CGG repeats in DNA and neurological disorders

... that some repetitive DNA sequences can make human chromosomes "fragile," i.e. appearing constricted or even ... as a result, stall replication. When this happens chromosomes can break during cell division. For the new ... the cellular checkpoints. As a consequence, chromosomes under-replicate, become fragile and break. ...

How chromosomes meet in the dark -- Switch that turns on X chromosome matchmaking

... has discovered the trigger that pulls together X chromosomes in female cells at a crucial stage of embryo ... also provide new insights into how other similar chromosomes spontaneously recognize each other and are bound ... in a step necessary to survival, one of the X chromosomes is silenced in each female cell to ensure that ...

Keeping chromosomes from cuddling up

... If chromosomes snuggle up too closely at the wrong times, the ... machines, proteins called condensin II, separate chromosomes by twisting them into supercoils that kink up and ... inside cells. Keeping specific parts of chromosomes from touching can change how the instructions ...

Two from one: Pitt research maps out evolution of genders from hermaphroditic ancestors

... the opportunity to observe the evolution of sex chromosomes in plants because that development is more recent. We wouldn't see this in animals because the sex chromosomes developed so long ago. Instead, we can study a ... exist among male and female plants. Sex chromosomes in these plants have two locior positions of ...

Rong Li Lab probes mechanism of asymmetry in meiotic cell division

... in live mouse oocytes, the team discovered that chromosomes can recruit to their vicinity a protein called ... and shortening and, in the process, push the chromosomes towards the outer edge of the oocyte. After the chromosomes reach the periphery, the actin filaments orient ...

New blood test for Down syndrome

... determine whether the fetus' cells contain extra chromosomes associated with several types of severe birth ... occurs when there are either too many or too few chromosomes in cells. Down syndrome, for example, is caused ... the point of screening was to spot extra chromosomes in the woman's blood sample. Whether the DNA ...

When cells go bad

... SALT LAKE CITY -- When a cell's chromosomes lose their ends, the cell usually kills itself to ... accumulate defects, including the wrong number of chromosomes or chromosomes that have exchanged pieces with each other. Those ...

Photosynthesizing bacteria with a day-night cycle contain rare chromosome

... more genes on the linear and the typical circular chromosomes then they'd have found with DNA sequencing alone. ... store their DNA in circular chromosomes. Linear chromosomes are generally found in more complex creatures ... one large circular chromosome and four small chromosomes called plasmids, and the linear one. On these, ...

Exploding chromosomes fuel research about evolution of genetic storage

... of genetic packing. Even so, the evolution of chromosomes in dinoflagellates, humans and other mammals seem ... . Packing the whole length of DNA into tiny chromosomes is problematic because DNA carries a negative ... "What takes care of neutralizing DNA, to allow chromosomes to condense?" Levi-Setti asked. "Most biology ...

Duke-NIEHS team shows how DNA repairs may reshape the genome

... (NIEHS) have shown how broken sections of chromosomes can recombine to change genomes and spawn new ... sequences allow the formation of new types of chromosomes (chromosome aberrations), and represent one ... repeated DNA sequences located on different chromosomes rather than from a simple re-joining of the ...

Death, division or cancer? Newly discovered checkpoint process holds the line in cell division

... cells that are unable to equally separate their chromosomes from dividing. The identities of the proteins ... so as to allow them to shuffle their deck of chromosomes to select for traits that promote drug resistance ... results in aneuploidy, the loss or gain of chromosomes in the daughter cells. This increases the risk of ...

X chromosome exposed

... UK, have revealed new insights into how sex chromosomes are regulated. A chromatin modifying enzyme helps ... enzyme distinguishes between male and female sex chromosomes in fruit flies and binds to different locations ... X chromosome in males, but also to all the other chromosomes in the nucleus. This suggests the enzyme as a ...

Scientists decipher fruit tree genome for the first time

... tree of life and the recent discovering of sexual chromosomes in its genome, Carica papaya is an excellent ... organism for the study of the evolution of sexual chromosomes in plants. Dr Navajas Prez, who at present is ... the determinant region of the sex in the sexual chromosomes of papaya and whose research career has been ...

Cold Spring Harbor Protocols features classic approaches for analyzing chromosomes

... elaborated principles have brought the study of chromosomes and chromatin structure to the forefront of ... "Mapping Protein Distributions on Polytene chromosomes by Immunostaining" takes advantage of the formidable size and structure of the large polytene chromosomes found in Drosophila salivary glands. These ...

How do you know whether you are male or female?

... in the fly suggested that it was the ratio of X chromosomes (the female chromosome, of which there are two ... fly, and just one in a male) to the non-sex chromosomes (the autosomes) that determined the sex of a fly ... dependent on the ratio, it is the number of X chromosomes that is important. Sex is determined during a ...

Feinstein researchers develop new genetic method and identify novel genes for schizophrenia

... mother and father, and identify pieces of chromosomes that are identical. They tested genetic material ... his colleagues identified nine regions along the chromosomes that might play a large role in triggering the ... one in the healthy group had identical chunks of chromosomes in four or more of these risk regions, subjects ...

Bioclocks work by controlling chromosome coiling

... genes in an ingenious fashion, simply by causing chromosomes to coil more tightly during the day and to relax ... known to possess a biological clock. The chromosomes in cyanobacteria are organized in circular ... the idea that the bioclocks influence on linear chromosomes is limited to certain specific regions, regions ...

X-effect: female chromosome confirmed a prime driver of speciation

... infertile hybrids when the species exchange X chromosomes than when they exchange any other chromosomes, ... effects of changes on the X. We inherit a set of chromosomes from each parent with each chromosome acting as a ... then it may be largely responsible for the X chromosomes unusually prominent role in the origin of new ...

Columbia to award 2007 Horwitz Prize to three generations of teacher-student scientists

... its own chromosomes, and what prevents the chromosomes from shrinking. Before the late 1970s and ... there were two mysteries about chromosomes. One, chromosomes are long lines of DNA so they have two ends, but cells recognize accidental breaks in chromosomes by their broken ends why dont the cells try to ...

Research points towards early cancer detection

... telomeres small structures at the end of human chromosomes which can play a crucial part in the onset of ... cause. The researchers also discovered how chromosomes can fuse together once they lose the protection of their telomeres. Chromosomal fusion causes the chromosomes to disintegrate, which can result in the ...

Surprise in the organic orchard -- a healthier worm in the apple

... from parents to offspring via one of the sex chromosomes - which helps to explain how the resistance increased so quickly. The sex chromosomes in humans are called X and Y, with XX females and ... males. This is reversed in moths, where the sex chromosomes are called Z and W, with ZZ males and ZW females. ...

First individual genome sequence published

... Craig Venter, that covers both sets of chromosomes that were inherited from each parent. Two ... 7.5 times, ensuring that each set of contributing chromosomes was covered over 3.2 times for greater than 96% ... the HuRef genome is diploid, each of the parental chromosomes could be directly compared to each other. One of ...

A unique arrangement for egg cell division

... process that is unique to egg cells, half of the chromosomes are eliminated from the egg before it is ... single egg cell with 23 instead of the normal 46 chromosomes in humans. It is crucial that the egg has half ... that the egg ends up with the correct number of chromosomes is a bipolar spindle consisting of protein ...

After dinosaurs, mammals rise but their genomes get smaller

... BLOOMINGTON, Ind. -- Evidence buried in the chromosomes of animals and plants strongly suggests only one group -- mammals -- have ... -- though you shouldn't expect to see noticeable changes in our chromosomes for a few million years yet. Lynch's group examined the genomes of ...

Female human embryos adjust the balance of X chromosomes before implantation

... and females have two sex chromosomes: X and Y. While females have two X chromosomes and no Y chromosome, males have one of each. As the X chromosome is much ... mice embryonic stem cell lines are made; these ES cells have two active X chromosomes and are capable of becoming any kind of cell in the body. As soon as the ...

Universitat Autonoma de Barcelona researchers first to clone mice in Spain

... transfer techniques, scientist collected mature oocytes, removed their chromosomes and substituted them for the nucleus of an adult somatic cell. The cloning ... oocytes and surrounding cumulus cells from several female mice. The chromosomes were extracted from each of the oocytes and substituted with a cell from ...

Scientists uncover mode of action of enzyme linked with several types of cancer

... have discovered a key mechanism used by cells to efficiently distribute chromosomes to new cells during cell multiplication. Published in the journal ... polo kinase, overexpressed in a broad range of human tumours, tells the chromosomes exactly when to condense during cell division." Misregulation of the ...

Stowers researchers develop whole genome sequencing approach for mutation discovery

... of EMS mutageneseis and into gene conversion events involving balancer chromosomes genetic tools used to prevent genetic recombination between homologous chromosomes during meiosis. Model organisms like fruit flies are used in research ...

'Freaks' help scientist unravel nature and nurture

... Or consider the fact that mammals, including humans, possess distinct chromosomes -- the X and Y -- for generating males and females, whereas many species ... animal. So, when it comes to the system that creates sex, temperature and chromosomes are interchangeable. "Such examples of interchangeability help reveal ...

Damon Runyon Cancer Research Foundation awards prestigious fellowships to 13 top young investigators

... of kinetochores, protein complexes that mediate the segregation of chromosomes during cell division. Discrepancies in the distribution of chromosomes in divided cells occur in many cancers and diseases such as Down's ...

Y chromosome and surname study challenges infidelity 'myth'

... and Professor Mark Jobling from the University of Leicester examined the Y chromosomes of over 1,600 unrelated men with forty surnames (including variations in ... such as Grewcock, Wadsworth, Ketley and Ravenscroft tended to share Y chromosomes that were very similar, suggesting a common ancestor within the past 700 ...

Scientists deconstruct cell division

... duplication of one mother cell into two daughter cells. In mitosis, the chromosomes condense and the nucleus breaks down. Fibrous structures called spindles ... "The mechanisms that cells use during division to partition both chromosomes and regulatory factors into their daughters are widely recognized as among ...

U-M researchers discover new genes that fuse in cancer

... Center have identified a series of genes that become fused when their chromosomes trade places with each other. These recurrent gene fusions are thought to ... School. Chinnaiyan's team was the first to identify rearrangements in chromosomes and fused genes in prostate cancer. Gene fusions had previously been known ...