Navigation Links
Insight into our sight: A new view on the evolution of the eye lens

The evolution of complex and physiologically remarkable structures such as the vertebrate eye has long been a focus of intrigue and theorizing by biologists. In work reported this week in Current Biology, the evolutionary history of a critical eye protein has revealed a previously unrecognized relationship between certain components of vertebrate eyes and those of the more primitive light-sensing systems of invertebrates. The findings help clarify our conceptual framework for understanding how the vertebrate eye, as we know it, has emerged over evolutionary time.

The work is reported by Sebastian Shimeld at the University of Oxford and colleagues at the University of London and Radboud University in The Netherlands.

Our sight relies on the ability of our eye to form a clear, focused image on the retina. The critical component in focusing is the eye lens, and the physical properties that underlie the transparency of the lens, as well as its ability to precisely refract light, arise from the high concentrations of special proteins called crystallins found in lens cells.

Fish, frogs, birds and mammals all experience image-forming vision, thanks to the fact that their eyes all express crystallins and form a lens; however, the vertebrates' nearest invertebrate relatives, such as sea squirts, have only simple eyes that detect light but are incapable of forming an image. This has lead to the view that the lens evolved within the vertebrates early in vertebrate evolution, and it raises a long-standing question in evolutionary biology: How could a complex organ with such special physical properties have evolved?

In their new work, Shimeld and colleagues approached this question by examining the evolutionary origin of one crystallin protein family, known as the ?-crystallins. Focusing on sea squirts, invertebrate cousins of the vertebrate lineage, the researchers found that these creatures possess a single crystallin gene, which is expressed in its primitive light-sensing system. The identification of the sea squirt's crystallin strongly suggests that it is the single gene from which the vertebrate ?-crystallins evolved.

The researchers also found that, remarkably, expression of the sea squirt crystallin gene is controlled by genetic elements that also respond to the factors that control lens development in vertebrates: The researchers showed that when regulatory regions of the sea squirt gene are transferred to frog embryos, these regulatory elements drive gene expression in the tadpoles' own visual system, including the lens. This strongly suggests that prior to the evolution of the lens, there was a regulatory link between two tiers of genes: those that would later become responsible for controlling lens development, and those that would help give the lens its special physical properties. This combination of genes appears to have then been co-opted in an early vertebrate during the evolution of its visual system, giving rise to the lens.


'"/>

Source:Cell Press


Related biology news :

1. Fundamental Finding Yields Insight into Stem Cells, Cancer; Opens Door to Drug Discovery
2. New Insights Into HIV Immunity Suggest Alternative Approach to Vaccines
3. Insight into natural cholesterol control suggests novel cholesterol-lowering therapy
4. Insight into DNAs weakest links may yield clues to cancer biology
5. Insight into the processes of positive and negative learners
6. Large-scale Computer Simulations Reveal New Insights Into Antibiotic Resistance
7. What Makes The Brain Tick, Tick, Tick: Researchers Gaining New Insights Into Brains Internal Clock
8. Molecular biology fills gaps in knowledge of bat evolution
9. Same mutation aided evolution in many fish species, Stanford study finds
10. Researchers trace evolution to relatively simple genetic changes
11. Family trees of ancient bacteria reveal evolutionary moves
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:12/15/2016)... , Dec. 15, 2016   WaferGen Bio-systems, ... held genomics technology company, announced today that on December ... Qualifications Department of The Nasdaq Stock Market LLC which ... bid price of WaferGen,s common stock had been at ... WaferGen has regained compliance with Listing Rule 5550(a)(2) of ...
(Date:12/15/2016)... , Dec. 14, 2016 "Increase in mobile ... market" The mobile biometrics market is expected to grow ... billion by 2022, at a CAGR of 29.3% between ... such as the growing demand for smart devices, government ... "Software component is expected to grow at ...
(Date:12/7/2016)... 2016 According to a new market research report "Emotion ... Expression, Voice Recognition), Service, Application Area, End User, And Region - Global Forecast ... USD 6.72 Billion in 2016 to USD 36.07 Billion by 2021, at a ... Reading ... MarketsandMarkets Logo ...
Breaking Biology News(10 mins):
(Date:1/20/2017)... -- http://www.Financialbuzz.com - According to ... of death worldwide. There were 8.2 million cancer related ... deaths increased gradually over time, the death rates have ... cancers continues to drive demand of biological therapies for ... Insights, Inc. cancer biological therapy market size was USD 61.3 ...
(Date:1/19/2017)... Research and Markets has announced the addition of the "Cancer ... Opportunity Analysis and Industry Forecast, 2014-2022" report to their offering. ... Cancer Biomarkers ... $15,737 million by 2022 from $6,521 in 2015, growing at a ... technologies segment accounted for more than half of the revenue share ...
(Date:1/19/2017)... HOUSTON , Jan. 19, 2017 ... announced the formation of its Medical/Clinical Advisory Board. ... industry veterans who enhance the range and depth ... development of its novel prenatal diagnostic tests.  These ... and strategic guidance for the company,s product development ...
(Date:1/19/2017)... Research and Markets ... the addition of the "Implantable Biomaterials Market Analysis ... report to their offering. Report Highlights: ... on current and future market trends to identify the investment opportunities ... base numbers Key market trends across the business segments, ...
Breaking Biology Technology: