Everything Science - Everything Science

Welcome to Everything Science

Snapdragons take the evolutionary high-road

Written by Everything Science

Aug 21, 2006 at 12:00 AM

Roses are red, violets are blue, but why aren't snapdragons orange? Norwich scientists from the John Innes Centre (JIC) and the University of East Anglia (UEA) in collaboration with the Universitïé Paul Sabatier (Toulouse, France) have developed a pioneering computer modelling technique that traces the evolutionary paths underlying flower colour variation in the model plant snapdragon (Antirrhinum).Their research, funded by the BBSRC and published today in the journal Science, shows how flower colour diversity has evolved in natural populations of these plants in the Pyrenees.

Bees that pollinate snapdragons prefer magenta or yellow coloured flowers to flower colours such as orange. (Photo taken by Annabel Whibley)

In the wild, only the plants with the most attractive flower colours are able to reproduce and thrive because the insects that pollinate them prefer certain colours. The bees that pollinate snapdragon find magenta and yellow flowers the most attractive; they do not find colours such as orange attractive and so flowers of this colour would not flourish in the wild due to lack of pollination. Scientists already know that natural colour variation is controlled by three genes: ROSEA and ELUTA affect the intensity and pattern of the magenta pigment anthocyanin and thirdly SULFUREA affects the distribution of the yellow aurone pigment. The researchers in this study wanted to understand how plants producing magenta or yellow flowers could evolve from a common ancestor without producing in-between non-attractive flower colours such as orange.

"This is a totally different way of looking at evolution and could lead to a better understanding of the rules that govern biodiversity" explains Coen, "If we can comprehend how Antirrhinum genes interact in their natural habitat, it may help us in the future to better preserve genetic diversity".

(2) Comments posted about this in the forum

Everything Biology

Written by Catarina Amorim

Aug 04, 2006 at 12:00 AM

One of the most important milestones in the evolution of life occurred when paired fins (and later limbs) appeared, leading to new types of locomotion. Now, in the advanced online issue of Nature1, scientists show that, although originating from different cell types, human limbs and median fins share a common developmental mechanism. These results support the idea that it was from median fins that all fins and limbs evolved, a hypothesis that has been around since the 19 century, but, until now, has never been proved.

Cells expressing inositol triphosphate receptors with an engineered binding site stained with snake venom

The earliest vertebrate fossils show only well-developed dorsal and ventral (median) fins what has led researchers to suspect that these were the basis for which all paired fins and limbs evolved. However, their different location (median versus side of the body) seemed to indicate that they appeared from different cells in the embryo, which challenged the common-origin idea.

In order to investigate the issue, Renata Freitas, a Portuguese scientist, together with Guang Jun Zhang and Martin J. Cohn, all working at the department of Zoology, University of Florida, studied the embryonic development of Catshark’s fins. Catsharks are sharks found in the Atlantic and owe their name to their flat heads and long, catlike eyes.

The researchers started by marking the different cells from the embryo and following their development, in order to understand which cells originated the different parts of the shark’s body. Next, they investigated the activity of different genes during fin development. From these two experiments, Freitas and colleagues discovered that the median fin of Catsharks, although originating from different embryonic cells, uses the same genes (Hox and Tbx18) during development as limbs and paired fins.

(1) Comments posted about this in the forum

Everything Archaeology

Written by Everything Science

Jul 28, 2006 at 12:00 AM

The origin of the brain mechanisms involved in human language is a much debated subject, especially whether these mechanisms appeared independently in humans or were already present in a common ancestor of human and non-human primates. But now, research just published in the advanced online issue of Nature Neuroscience 1, found that Rhesus macaques when listening to other monkeys’ calls activate brain areas equivalent to the ones used for language in humans supporting the hypothesis that the neural basis for language existed already in a common ancestral. The discovery is a major step in understanding better language origins and evolution.

Although monkeys do not possess language, they do have an extended repertoire of sounds that have specific functions such as alerting to the presence of predators and marking various social interactions or emotional states. Interestingly, they have been shown to have regions in the brain similar to the Perisylvian area, although until now their functional significance was unknown, as was their link to the equivalent human region.

The acquisition of language is one of the most important adaptations during human evolution. Language created new human interactions and allowed ideas to bridge time and space. Among humans, babies as young as four weeks can respond to about 40 consonants, as differences in their sucking and heartbeats rates show. This ability seems to be innate, as babies from English-speaking parents react to consonants in Japanese that not exist in the English language. By the age of six, when the child enters school, the ability to react to sounds to which he/she has not been exposed in their own language is severely reduced, probably because at this point brain development rate decreases, and that is also why, after this age, it is so much more difficult to learn a second language.

Two main language centres have been identified in the human brain: Broca’s area, in the frontal lobe and Wernicke’s area, posteriorly. Both areas are found within a larger surface called the Perisylvian region, believed to be associated with language comprehension and production.

(1) Comments posted about this in the forum

Wireless and Handheld

Written by IST RESULTS

Jul 23, 2006 at 12:00 AM

As mobile devices become increasingly ubiquitous and play ever more significant roles in our lives, ensuring the trustworthiness and security of the information being exchanged has never been more important. But clearly, strong security should not be at the expense of user acceptance. European researchers are employing biometrics and digital signing to provide a solution.

http://istresults.cordis.lu/

Though security applications that verify a person’s identity based on their physical attributes, such as fingerprint readers or iris scanners, have been in use for some time, biometric security has only recently started to appear in mobile phones, PDAs and notebook computers where the need for miniaturisation represents a technological challenge.

So far biometric data has been used to tie the device to a person to prevent it from being used illegitimately if lost or stolen. But the IST project SecurePhone is taking a new approach, employing physical attributes to enable the user to digitally sign audio, text or image files, providing proof of their origin and authenticity.

“As far as we know there is no other biometrically-enabled digital signature application available for mobile devices that can guarantee security by storing and processing all sensitive information on the device’s SIM card,” explains SecurePhone technical coordinator Roberto Ricci at Informa in Italy. “Because biometric data never leaves the device’s SIM card and cannot be accessed, except by the verification module which also runs on the SIM card, the user’s biometric profile is completely safe. This is important to meet the highest privacy requirements.”

(1) Comments posted about this in the forum

More...

<< Start < Previous 1 2 3 4 5 6 7 8 9 10 Next > End >>

Results 41 - 48 of 175