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Humans construct boundaries -- around our homes, our neighborhoods, and our nations -- to bring order to a chaotic world. But we rarely consider how these boundaries affect other creatures. In this episode of Think Like A Scientist, we meet conservation photographer Krista Schlyer, who has spent the last seven years documenting the environmental effects of the U.S./Mexico border wall, and biologist Jon Beckmann, who studies how man-made barriers influence the movement of wildlife. Schlyer and Beckmann have seen damaging impacts of the border wall firsthand, but they remain optimistic. Humans probably won't stop constructing walls and fences any time soon, but planning our boundaries with wildlife in mind can help prevent these structures from causing environmental harm.

As the genomes of more and more species are sequenced, geneticists are piecing together an extraordinarily detailed picture of the molecules that are fundamental to life on Earth. With modern techniques, we can not only trace how the bodies of animals have evolved, we can even identify the genetic mutations behind these changes and, as we recently reported, genes sometimes evolve in surprising ways. Here though, in celebration of the versatility of DNA, New Scientist presents five classic examples of gene evolution.

An international team led by Professor Itai YanaAi of the Technion-Israel Institute of Technology Department of Biology made the discovery after using an extraordinarily powerful technique known as CEL-Seq. CEL-Seq monitors individual cells for their gene activity (as detected via mRNA)-and they applied it across 10 different species, with CEL-Seq being applied to 70 embryos per species. In particular, they were interested in whether the animal classification of phylum-which separates animals into groups according to their body plans-is actually a useful tool for placing animals into groups, as well as what genetic attributes are the same and different between the different phyla.

Six years ago, Yale University's Stephen Stearns and colleagues took advantage of a long-running study in Framingham, Massachusetts, to assess whether the effects of natural selection could be discerned among the people in the multigenerational study population. Over the last seven decades, public-health researchers have been monitoring the residents of Framingham, noting their vital statistics as well as blood sugar and cholesterol levels to understand the factors that lead to heart disease. As the initial group of research subjects got older, the study started to include their children, and then their grandchildren. The records provide a unique view of the health of a segment of the American population since 1948.

HIV jumped from apes to humans at least four times, as evidenced by genetically distinct groups of the virus that have been detected: M, N, O, and P. While N and P have had little impact, M is responsible for the pandemic affecting millions of individuals, and O has infected another 100,000.

 A team of scientists has announced that the age of the synthetic chromosome is upon us, as a study published in Science today reveals how the group was able to construct a yeast chromosome from scratch - an experiment that allowed the team to make fully functional "designer yeast."

Cattle with the mouse gene SP110 added to their genomes have immune cells that are better at slowing the growth of Mycobacterium bovis and are less susceptible to developing the internal symptoms of tuberculosis (TB), according to a study published this week (March 2) in PNAS.

This case study details the historical discovery of the structure of DNA. Images of this key molecule are as iconic as those of the Mona Lisa, and identifying its structure has proven to be as intriguing a mystery for scientists as the reason behind Mona Lisa's smile has been for art historians. The case is woven together by a series of fictional diary entries that detail the history of the discovery of DNA's structure, the major players involved, their ethical dilemmas, and the role of women in science. The case is designed for a high school course or introductory undergraduate genetics/ biochemistry courses. It can also be used as an interdisciplinary case study bridging genetics, bioethics, art, and the status of women in science. Designed as an interrupted case, it may be used in its entirety or in parts that pertain to a particular topic or discipline. No prior knowledge of genetics is required.

THE prospect of creating intelligent designer babies has been the subject of ethical debate for decades, but we have lacked the ability to actually do it. That may now change, thanks to a new method of testing an embryo's genes that could soon be available in some IVF clinics in the US, New Scientist can reveal.

Scientists have created an "artificial womb" in the hopes of someday using the device to save babies born extremely prematurely. So far the device has only been tested on fetal lambs. A study published Tuesday involving eight animals found the device appears effective at enabling very premature fetuses to develop normally for about a month.

An environmentally dependent method to excise particular genes and eliminate genetically modified organisms (GMOs) if they leave the lab, published this week (May 19) in Nature Communications, uses an inducible CRISPR/Cas9 genome-editing system to snip out vital pieces of the E. coli genome.

Redwood trees, those ancient living monuments to California's past, are as mysterious to science as they are magnificent, so a team of researchers led by a San Francisco conservation group is attempting to unlock the genetic secrets of the towering conifers. Scientists affiliated with the nonprofit Save the Redwoods League are attempting for the first time to sequence the genomes of coast redwood trees and their higher-elevation cousins, the giant sequoias, a complex and expensive undertaking that experts hope will help preserve the trees' ancient groves as the climate changes over the next century.

The external environment's effects upon genes can influence disease, and some of these effects can be inherited in humans. Studies investigating how environmental factors impact the genetics of an individual's offspring are difficult to design. However, in certain parts of the world in which social systems are highly centralized, environmental information that might have influenced families can be obtained. For example, Swedish scientists recently conducted investigations examining whether nutrition affected the death rate associated with cardiovascular disease and diabetes and whether these effects were passed from parents to their children and grandchildren (Kaati et al., 2002). These researchers estimated how much access individuals had to food by examining records of annual harvests and food prices in Sweden across three generations of families, starting as far back as the 1890s. These researchers found that if a father did not have enough food available to him during a critical period in his development just before puberty, his sons were less likely to die from cardiovascular disease. Remarkably, death related to diabetes increased for children if food was plentiful during this critical period for the paternal grandfather, but it decreased when excess food was available to the father. These findings suggest that diet can cause changes to genes that are passed down though generations by the males in a family, and that these alterations can affect susceptibility to certain diseases. But what are these changes, and how are they remembered? The answers to questions such as these lie in the concept of epigenetics.

Autism is rooted in genetics, including the mutation of certain genes that result in a failure of neurons in the brain to properly connect. Based on earlier genetic research funded by Autism Speaks, such as the Autism Genome Project (AGP), scientists have discovered some of these genes. But much more gene discovery needs to take place. The Autism Genome 10K Project will mark a substantial leap forward on this journey. The Autism Genome 10K Project builds on the successes of Autism Speaks' Autism Genetic Resource Exchange program (AGRE), a high-quality collection of more than 12,000 DNA samples from families affected by autism. The AGRE program has facilitated many high-impact scientific discoveries in recent years, including the risk genes discovered by the AGP and other researchers. With BGI sequencing the full complement of 10,000 samples collected by AGRE and collaborators in China, Autism Genome 10K leverages BGI's cutting-edge expertise and globally unrivaled capacity for high-quality genome sequencing.

This case study presents the fictional tale of two neighboring towns that have recently experienced a growth boom and are now suffering the environmental consequences. The case provides an opportunity to explore a wide variety of anthropogenic causes of natural capital degradation. Students are assigned the role of scientists working for the regional Department of Environmental Resources Management, and it is their job to discover the underlying causes for a wide variety of citizen complaints and to suggest reasonable and cost effective solutions. The case may be assigned as a recap activity after teaching a unit on natural capital degradation. The case includes a PowerPoint presentation as well as three lab activities that are included in the teaching notes. The case would be appropriate for high school or lower level undergraduate ecology or environmental science courses.

Quintana-Murci and his colleagues also took advantage of a previously published map of areas of the human genome where Neanderthal genes are present, showing that innate immune genes are generally more likely to have been borrowed from Neanderthals than genes coding other types of proteins. Specifically, they noted that 126 innate immune genes in present-day Europeans, Asians, or both groups were among the top 5 percent of genes in the genome of each population most likely to have originated in Neanderthals. The cluster of toll-like receptor genes, encoding TLR 1, TLR 6, and TLR 10, both showed signs of having been borrowed from Neanderthals and having picked up adaptive mutations at various points in history. Meanwhile, a group led by Janet Kelso of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, used both the same previously published Neanderthal introgression map that Quintana-Murci used and a second introgression map. The researchers searched for borrowed regions of the genome that were especially long and common in present-day humans, eventually zeroing in TLR6, TLR10, and TLR1. These receptors, which detect conserved microbial proteins such as flagellin, are all encoded along the same segment of DNA on chromosome four.

Exposing mice to long periods of light each day led them to put on fat, likely because their energy-burning brown fat wasn't in good shape.  Mice exposed to long periods of light didn't eat more or exercise less than mice that kept to a 12-hour day, but their brown fat activity dropped, researchers reported in PNAS this week (May 11).

In the second film of the Great Transitions trilogy, paleontologist Julia Clarke takes us on a journey to uncover the evidence that birds descended from dinosaurs. The discovery of Archaeopteryx in a quarry in Germany in the early 1860s provided the first clue that birds descended from reptiles. But what kind of reptile? In the last 40 years, scientists have identified many shared features between birds and two-legged carnivorous dinosaurs called theropods. The film illustrates many of the practices of science, including asking important questions, formulating and testing hypotheses, analyzing and interpreting evidence, and revising explanations as new evidence becomes available.

Have you heard of Alexander von Humboldt? Not likely. The geologist turned South American explorer was a bit of an 18th century super scientist, traveling over 24,000 miles to understand the relationship between nature and habitat. George Mehler details Humboldt's major accomplishments and why we should care about them today.

" IBM scientists have been able to differentiate the chemical bonds in individual molecules for the first time using a technique known as noncontact atomic force microscopy (AFM)."