Organised by the National Human Genome Research Institute each year, National DNA Day in the US on 25 April celebrates the discovery of DNA’s double helix in 1953 and the completion of the Human Genome Project in 2003. Here, we explore the history of DNA and its discovery’s unparalleled effect on science, medicine and the way we now understand the human body.
Discovering DNA’s structure
Using the pictures that she had taken, Franklin was able to calculate the dimensions of the strands and found the phosphates were on the outside of the DNA helix.
Rosalind Franklin working in her lab. Image: Wikimedia Commons
Meanwhile, at the University of Cambridge, James Watson and Francis Crick deduced the double-helix structure of DNA, describing it as ‘two helical chains each coiled round the same axis’ following a right-handed helix containing phosphate diester groups joining β-D-deoxyribofuranose residues with 3’,5’ linkages.
The discoveries made by these scientists would propel the study of genetics into the modern science we know today. Crick and Watson were awarded the Nobel Prize for Physiology or Medicine alongside Maurice Wilkins, who worked with Rosalind Franklin, in 1962. You can read their original paper here.
Dolly the sheep
Dolly on display at the National Museum of Scotland, UK.
Dolly is arguably the most famous sheep in the world, having been the first mammal to be cloned from an adult cell. Born in 1996, Dolly was part of a series of experiments at the Roslin Institute in Edinburgh to create GM livestock that could be used in scientific experiments.
She was cloned using a technique called somatic cell nuclear transfer, where a cell nucleus from one adult is transferred into an unfertilised developing egg cell of another that has had its nucleus removed, which is then implanted into a surrogate mother.
The scientific legacy of Dolly the sheep. Video: Al Jazeera English
Dolly lived until 2003 when she was euthanised after contracting a form of lung cancer. Many speculated that Dolly’s early death was related to the cloning experiment but extensive health screening throughout Dolly’s life by the Roslin Institute suggest otherwise.
Her creation has led to further cloning projects and could be used in the future to preserve the populations of endangered or extinct species, and has led to significant developments in stem cell research.
In 2009, Spanish researchers announced the cloning of a Pyrenean ibex, which has been extinct since 2000, and was the first cloning of an extinct animal. Unfortunately, the ibex died shortly after birth but there have been a few successful stories since then.
The Human Genome Project
Beginning in 1990 and finishing in 2003, the Human Genome Project was an international research initiative that aimed to write the entire sequence of nucleotide base pairs that make up the human genome, including the mapping of all its genes that determine our physical and functional attributes.
The publicly funded $3bn project was able to map 99% of the human genome with 99.99% accuracy, which included its 3.2bn Mega-base pairs, 20,000 genes and 23 chromosome pairs, and has led to advancements in bioinformatics, personalised medicine and a deeper understanding of human evolution.
In April, EU Members States voted for a near complete ban of the use of neonicotinoid insecticides – an extension to restrictions in place since 2013. The ban, which currently includes a usage ban for crops such as maize, wheat, barley, and oats, will be extended to include others like sugar beet. Use in greenhouses will not be affected.
Some studies have argued that neonicotinoids contribute to declining honeybee populations, while many other scientists and farmers argue that there is no significant field data to support this.
In response to the recent ban, SCI’s Pest Management Science journal has made a number of related papers free to access to better inform on the pros and cons of neonicotinoids.
Like to know more about neonicotinoids? Click the links below…
Robin Blake and Len Copping discuss the recent political actions on the use of neonicotinoids in agriculture, and the UK’s hazard-based approach following field research unsupportive of an outright ban on the insecticides.
Conflicting evidence on the effects of neonicotinoids on the honeybee population has beekeepers confused and has led to the increase in the use of older insecticides, reports one beekeeper.
Following the 2013 EU partial ban on neonicotinoids, experts called for good field data to fill knowledge gaps after questioning of the validity of the original laboratory research. To encourage future debate, realistic field data is essential to discouraging studies using overdoses that are not of environmental relevance.
This paper describes the consequences of the ban on neonicotinoid seed treatments on pest management in oilseed rape, including serious crop losses from cabbage stem flea beetles and aphids that have developed resistance to other insecticides.
The Research Articles
Particle size is one of the most important properties affecting the driftability and behaviour of dust particles scraped from pesticide dressed seeds during sowing. Different species showed variable dust particle size distribution and all three techniques were not able to describe the real-size distribution accurately.
Aside from particle size, drift of scraped seed particles during sowing is mainly affected by two other physical properties – particle shape and envelope density. The impact of these abraded seed particles on the environment is highly dependable on their active ingredient content. In this study, the envelope density and chemical content of dust abraded from seeds was determined as a function of particle size for six seed species.
Substantial honey bee colony losses have occurred periodically in the last decades, but the drivers for these losses are not fully understood. Under field conditions, bee colonies are not adversely affected by a long‐lasting exposure to sublethal concentrations of thiacloprid – a popular neonicotinoid. No indications were found that field‐realistic and higher doses exerted a biologically significant effect on colony performance.
In May 2018, the first full-scale mobile marine plastics collection system, developed by The Ocean Cleanup, will leave San Francisco, California, bound for the ‘Great Pacific Garbage Patch,’ also known as the Pacific trash vortex. The plan, ultimately, is to use 60 of these $5m systems to clean up half of the debris in the Pacific Garbage Patch within five years, according to Boyan Slat, CEO of Netherlands foundation The Ocean Cleanup, speaking at the Cefic Chemical Congress held in Vienna, Austria, at the end of October 2017.
Each collection system comprises a 1km U-shaped barrier, which floats on the surface of the ocean and supports a 4m deep screen to channel floating plastic debris to a central collection point, for future recycling. A 100m prototype system has already been tested in the North Sea.
The system will leave from the San Francisco bay area. Image: Giuseppe Milo
The environmental cost of the Pacific’s plastic waste currently stands at roughly $13bn/year, while an estimated 600 wildlife species are threatened with extinction partly as a result of ingesting it. Plastic microbeads and particles only represent 5% of the plastics in the oceans, ‘but the remaining 95% will break down into small particles and chemicals that are already in the tuna we eat,’ Slat said. The larger plastics debris are all found in the top 4m of the oceans, the same depth as the system’s screens.
Plastic debris can end up in the food we eat. Image: Pixabay
Also speaking in Vienna, Emily Woglom, executive VP, Ocean Conservancy, said that 8m t/year of plastics goes into the oceans – ‘one city dump truck every minute’; between 2010 and 2025 the amount in the oceans will double. As much as ‘30% of fish on sale have plastics in them,’ she said. Most of the plastics now come from the developing economies, mainly in Asia, she added, noting that the Trash Free Seas Alliance, founded by the Ocean Conservancy and supported by the American Chemistry Council, Dow Chemical, P&G and the World Plastics Council as well as several big-name food and beverage companies have recently adopted the goal of launching a $150m fund for waste management in South East Asia.
How we roll. Video: The Ocean Cleanup
Meanwhile, Slat says that the mobile collection systems can also be used to trap plastic pollution closer to the source, for example in rivers and estuaries. Researchers at The Ocean Cleanup estimate that rivers transport between 115 and 241 m t/years of plastic waste into the oceans, with two-thirds coming from just 20 rivers, mostly in Asia.
The Pacific trash vortex forms as a result of circular ocean currents created by wind patterns and the forces created by the Earth’s rotation. Similar gyres are found in the South Pacific, Indian Ocean, and North and South Atlantic.