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To form an egg or sperm cell, a cell splits into two during meiosis so each resulting cell only contains half the chromosomes of the original.   ED RESCHKE/GETTY IMAGES Gene-swapping in human sperm and eggs can increase genetic mutations in children By  Erika K. Carlson Jan. 24, 2019 , 4:00 PM When parents pass their genes down to their children, they give the kids remixed versions of their own chromosomes. And that remixing of chromosomes can increase the chances that the child’s DNA will also mutate in certain locations, according to a high-precision study of the DNA of more than 150,000 people. The data in this study may be helpful for understanding mutation rates in humans and measuring how quickly we are evolving. “The scale of the study is just unprecedented,” says geneticist Molly Przeworski of Columbia University, who was not involved in the project. “The resource alone is going to be a boon for the field.” Your genome consists of long strands of t...

The ocean is full of drifting DNA. The United States needs to collect it, researchers say By  Alex Fox Jan. 22, 2019 , 1:25 PM U.S. government agencies monitoring fisheries, endangered species, and environmental impacts ought to leverage the DNA present in every drop of seawater, say the organizers of a conference on marine environmental DNA (eDNA), held at Rockefeller University in New York City in November 2018. Biological surveys based on eDNA are reliable and poised to cut costs and save time, they argue in  a report  released last week. The report calls for the U.S. National Oceanic and Atmospheric Administration (NOAA) and other government agencies that survey marine life to add the technology to their standard palette of assessment techniques. “We are exploring all pathways to get the critical information of what animals are where and how many there are,” says conference attendee Michael Weise, who manages the Office of Naval Research’s Marine Mammals a...

Study of Planktonic forms of lakes of Mysore city “Phytoplankton” is the collective name for the group of microscopic, aquatic photosynthetic organisms which are abundant in freshwater Lakes. During favourable conditions dense aggregations called “blooms” occurs which often causes fish kills or render the water unfit for any use. They have very high biological activity and are important is sustaining life in Lake waters. They are influenced by climatic changes and by variations in the physical and chemical constituents of the water and the uncontrolled conditions lead to water pollution. The presence of phytoplankton in freshwater bodies is a widely accepted indicator of water quality. However, identification of the algal species, the knowledge of the algal cell number, or the physiological state of cells may also be important in providing a true picture of the water quality or trophic state. The samples from both the lakes were collected in 30 mL vials. Few drops of Lugol’s i...

A plant’s sap is responsible for transporting sugars from the site of their manufacture (the leaves) to growth centers (further up the branch or trunk of the plant). And the system has to strike a delicate balance: if the sap has a low concentration of sugars, there isn’t much energy flowing to the plant; if, on the other hand, there are lots of sugars in the sap it becomes too thick to pump efficiently. It’s a situation a lot like transporting any payload through a traffic artery, be that a paved highway or a canal with kayakers. So what’s in a plant’s best interest? Researchers  reviewed  41 species of plants and found that, though most plants have sugar concentrations of 18 to 21 percent, the optimal sugar concentration is a bit higher: 23.5 percent. That’s pretty sweet—twice as sweet as a Coke, for instance (10 percent sugar). At the other end of the spectrum, maple syrup—a distillation of the watery maple sap—is quite viscous with a sugar concentration of 65 perce...