Fig.1. The Suntry "blue" rose is at the center of a shift in plant engineering
(Credit: BlueRoseMan, 2011)
From laser technology to DNA barcoding, the modern study of plants involves increasingly unique approaches to examining preserved specimens. This week in the news, we remember the history of herbaria, grow miniature vegetables, and start a home-grown plant engineering movement that seeks to shake up genetics!
Editor's Note: This is the first in a series of videos we will release in 2016 about the use of scientific collections and DNA technology.
When it comes to reliable plant identification in their work,
Ida Lopez and Dr. Caroline Puente, of the Smithsonian’s National Museum of
Natural History (NMNH) Plant DNA Barcoding Project, botany department, have a
tool most associate with the retail world. But barcodes, in this case DNA
barcodes, are creating many research opportunities in the scientific world in
areas of ecology, evolution, conservation and more.
A DNA barcode, which is made up of approximately 600 base pairs of the species’ entire genome,
can authentically identify down to the species level. A commonly used barcode marker
in animals is
the mitochondrial gene cytochrome oxidase 1 (CO1). This gene however does
not successfully identify plant species.
“We knew that in animals the CO1 site was very indicative,”
Lopez said. “Zoologists could just sequence this one site and tell exactly what
type of animal it was.”
Because the CO1 gene has evolved slower in plants, it is not
useful to identify plant species. So around 10 years ago, researchers, under the direction of John Kress,NMNH Department of Botany curator,began looking for candidate genes
in plants. They found that they needed a combination of at least two
chloroplast regions - rbcL and trnH-psbA -to
create a workable plant DNA barcode. Today matK, another chloroplast
gene, and a nuclear region – the Internal Transcribed Spacer (ITS) are
added to insure success.
While
researchers agree that fresh tissue is ideal for extracting DNA, Puente said
that in cases where scientists can’t revisit a location to collect samples,
museum collections, in this case botanical specimens, are invaluable.
“One of the
big advantages of DNA barcoding is that we do not need a lot of tissue material”
Puente said. “... You can barcode small organisms such as insects and bacteria
- anything that has DNA even in limited amounts.”
A tissue
sample just a little larger than a pencil eraser is enough for DNA extraction
and barcoding. Lopez and Puente have specimens at their fingertips in the
Department of Botany’s vast collection at NMNH. The collectionholds 5 million specimens, with
approximately 105,000 of those serving as type
specimens. To learn more about Lopez and Puente's work, visit The Plant DNA Barcode Project.
References
W. John Kress, Carlos García-Robledo, Maria Uriarte, and David L. Erickson (2014, November 19). DNA barcodes for ecology, evolution, and conservation. CellPress, vol 30 (1): 25-35. doi: 10.1016/j.tree.2014.10.008
W. John Kress, David L. Erickson. (2007, June 6) A Two-Locus Global DNA Barcode for Land Plants: The Coding rbcL Gene Complements the Non-Coding trnH-psbA Spacer Region. PLOSOne(6): e508. doi: 10.1371/journal.pone.0000508
From microscopic organisms to lunar rocks, these collections offer a rare view of our solar system. In the news this week are visits with curators who collect comet dust, find new species, protect banana crops, and more!
At 5:30 a.m. on July 16, 1945, the first nuclear weapon was detonated under code name “Trinity.” Although disagreement still remains as to the start or nature of the Anthropocene, many scientists agree that nuclear weapons testing caused a widespread anthropogenic signal in the geologic record. In a couple short decades, these weapons tests doubled the amount of the radioactive isotope carbon-14 in our atmosphere. The isotope in the air entered plants during photosynthesis and animal tissues as animals ate the plants, leaving behind a radioactive trace in the natural world.
AlthoughÖtzi the Iceman offers scientists an unprecedented view of early European life, such direct physical evidence is not always available. This week, researchers used parasites to track Romans, mammoth bones to study Arctic dwellers, and more to overturn previously held assumptions about the ancient world.
In 1991, two hikers stumbled upon a mummy high in the Ötztal Alps, right on the border between Austria and Italy. This mummy - nicknamed Ötzi, or the Iceman - is Europe’s oldest natural human mummy and is arguably one of the most studied cadavers in science. From his eye color (brown) to his dental health (poor), Ötzi reveals an amazing amount about how Europeans looked and lived 5,300 years ago. An international group of scientists released a study last week in the journal Sciencethat added yet another detail to the treasure trove of research on the corpse, which may inform our understanding of ancient human migration into Europe.
An editorial based on SciColl’s 2014 workshop on emerging infectious diseases has just been released in the Proceedings of the National Academy of Sciences. From the first case to a worldwide eradication effort, scientific collections are necessary for disease research and response. This week, public health officials join in the fight against mysterious diseases and call for increased communication and collaboration.
