Antifreeze fish make sense out of junk DNA

Apr 04, 2006

Scientists at the University of Illinois have discovered an antifreeze-protein gene in cod that has evolved from non-coding or 'junk' DNA. Since the creation of these antifreeze proteins is directly driven by polar glaciation, by studying their evolutionary history the scientists hope to pinpoint the time of onset of freezing conditions in the polar and subpolar seas.

Professor Cheng will present her latest results at the Annual Main Meeting of the Society for Experimental Biology in Canterbury on Tuesday the 4th April.

Fish such as cod that live in subzero polar waters have evolved to avoid freezing to death by using special antifreeze proteins that work by binding to ice crystals to prevent the crystals growing larger and causing problems. Most of these antifreeze proteins evolve by natural selection from existing proteins when the DNA coding for them duplicates itself and changes over time to give new functions. However, Professor Christina Cheng and her group have found the gene for the cod antifreeze protein has come from a non-coding region of their DNA known as "junk DNA".

"This appears to be a new mechanism for the evolution of a gene from non-coding DNA", says Professor Cheng, "3.5 billion years of evolution of life has produced many coding genes and conventional thinking assumes that new genes must come from pre-existing ones because the probability of a random stretch of DNA somehow becoming a functional gene is very low if not nil. This cod antifreeze gene might be an exception to this because it consists of a short repetitive sequence that only needs to be duplicated four times to give a fully functioning protein".

Source: Society for Experimental Biology

Explore further: Research geared to keep women from fleeing IT profession

add to favorites email to friend print save as pdf

Related Stories

New study charts the global invasion of crop pests

48 minutes ago

Many of the world's most important crop-producing countries will be fully saturated with pests by the middle of the century if current trends continue, according to a new study led by the University of Exeter.

Zambia lifts ban on safari hunting

2 hours ago

Zambia has lifted a 20-month ban on safari hunting because it has lost too much revenue, but lions and leopards will remain protected, the government said Wednesday.

Recommended for you

Bronze Age wine cellar found

11 hours ago

A Bronze Age palace excavation reveals an ancient wine cellar, according to a study published August 27, 2014 in the open-access journal PLOS ONE by Andrew Koh from Brandeis University and colleagues.

Orphaned children can do just as well in institutions

11 hours ago

The removal of institutions or group homes will not lead to better child well-being and could even worsen outcomes for some orphaned and separated children, according to new findings from a three-year study across five low- ...

User comments : 0