Scientists identify genetic markers in grapevine’s genome to make better grapes

Washington, March 24 (ANI): Reports indicate that a team of Agricultural Research Service (ARS) researchers has found a way to make better grapes by developing a way to identify genetic markers in the grapevine’s genome that can be linked with specific traits, such as fruit quality, environmental adaptation, and disease and pest resistance.

Computational biologist Doreen Ware, geneticists Edward Buckler and Charles Simon, and research leader Gan-Yuan Zhong have developed a relatively fast and inexpensive way to identify genetic markers not only in grapes, but also in other crops by using modern sequencing approaches.

The researchers used the technology to sequence representative portions of the genomes from 10 cultivated grape varieties, six wild varieties and the clone of Pinot Noir originally sequenced by scientists in 2007.

They developed filters that allowed them to make corrections for common sequencing errors, and discovered thousands of high-quality single nucleotide polymorphisms, or SNPS, which are genetic markers that can serve as signposts for showing how plants are related to each other.

They then used 9,000 of those SNPs in a custom-designed assay to examine DNA patterns at defined points along each cultivar’s genome.

They found that the SNPS contained enough data to identify the relationships and geographic origins of the cultivars.

Improved technology is expected to make it possible to one day sequence the entire genomes of large numbers of grapes.

But in the meantime, the work will help researchers identify portions of the grape genome where they can find genes that confer desirable traits, offering better information for breeders developing new varieties.

The technique also should make it easier to identify the origins of other types of plants, characterize relationships in other plant collections, and accelerate genetic mapping efforts in a number of crop species. (ANI)

How proteins travel in the brain

London, Apr 22 (ANI): While proteins are known to be at the centre of every life process, and carry out all sorts of work by going to the cell, what guides these basic molecules towards their target cells in the brain has been unknown, until now.

Don Arnold- a molecular and computational biologist at USC College-and colleagues have now solved the mystery for key proteins in the brain.

“There’s no little man sitting there, putting the protein in the right place. Proteins have to have in them encoded information that tells them where to go in the cell,” Nature quoted Arnold as saying.

Neurons have separate structures for receiving signals (dendrites) and for sending them (axons).

The electrical properties of both types of neurons depend on different proteins.

But the proteins travel in bubbles, or vesicles, powered by motors known as kinesins that travel along tiny molecular paths.

Even though the paths point to both axons and dendrites, dendritic proteins end up in dendrites, and axonal proteins go to the axons.

The researchers discovered a crude but effective sorting mechanism, in which firstly kinesins blindly carry both types of proteins towards the axon.

But, dendritic proteins enable the vesicles transporting them to bind to a second motor, known as myosin, that walks them back into the dendrite.

The filter ensures that only axonal proteins make it into the axon, while the others are caught by the second motor and diverted to the dendrite.

“This mechanism fishes these things out of the axon,” said Arnold.

Once in the dendrite, the proteins either land in a place where they can do their electrical work or they move back towards the axon, only to be fished out again.

Arnold said that the process looks inefficient, “but it is very effective.”

The discovery could allow finer control over neurons for basic research or for treatment of neurological disorders.

Also, scientists could target only dendrites or axons in a neuron for studying its outgoing or incoming impulses.

Apart from these applications, the study contributes a lot to the understanding of the brain and of protein transport in general.

“It’s a very basic question, something people have been wondering about for a long time,” said Arnold.

The study is appearing online this week in Nature Neuroscience. (ANI)

‘T. rex’ protein may have contained traces of ostrich rather than chicken

London, Feb 28 (ANI): A fresh analysis of ancient protein from a fossilized Tyrannosaurus rex has revealed traces of ostrich haemoglobin in the original samples, which in an earlier study, were determined to have matched that of a chicken.

In the previous study, researchers identified seven fragments from a protein called collagen1, found in connective tissue, and said their sequences most closely matched the chicken version of the protein2.

The samples came from the fossilized femur of a T. Rex. As well as further strengthening the evidence for the link between dinosaurs and birds, the findings would make the protein the oldest ever to be sequenced – by around 68 million years.

Now, according to a report in Nature News, Martin McIntosh, a mass spectrometrist at the University of Washington in Seattle, has claimed to have identified ostrich haemoglobin protein in a cache of 48,000 protein spectra.

McIntosh suspects the samples were somehow contaminated with proteins from modern species.

McIntosh’s findings came to light on February 23 at the sixth annual meeting of USHUPO – part of the international Human Proteome Organisation – in San Diego, California.

In the course of a lecture, Pavel Pevzner, a computational biologist at the University of California, San Diego, cited McIntosh’s work and called for an independent review of the original results.

He said that his analysis provides statistical support for two of seven collagen proteins the Science authors said were from T. rex.

But now, the contamination issue has raised new concerns about the validity of the earlier findings.

McIntosh also wrote a technical comment for Science, suggesting contamination on the basis the haemoglobin spectra – but it was rejected.

Peer reviewers said that one fragment of ostrich haemoglobin was not enough to suggest contamination had occurred.

Though McIntosh accepted that his paper doesn’t prove contamination, he still believes the samples may be tainted. (ANI)