In praise of the Y chromosome

first_imgIn comparison to the X chromosome, says David Page, the Y chromosome is a “demure, rather shy little fellow” traditionally believed by scientists to be decaying or stagnating to the point where some researchers have predicted its eventual extinction.“I have spent the better part of the last 25 years defending the honor of this small, downtrodden chromosome in the face of numerous insults to its character,” said Page, director of the Whitehead Institute and a professor of biology at Massachusetts Institute of Technology, during a lively lecture Thursday (April 15) titled “The Evolutionary and Genetic Basis of Human Reproduction,” the final talk this semester in the “Evolution Matters” series sponsored by the Harvard Museum of Natural History.Talking as if he were teaching a class, Page dispensed with the traditional format of holding a question-and-answer session at the end of his lecture, and instead invited audience participation. He began with a “crash course” he called “Human Genome 101,” asking questions such as “How many cells do you have in your body?” (10 trillion); “How many genomes per cell?” (two, except for in gametes, which have one); and the trickier “How old is sex?” (that depends whether you’re talking about bacteria, yeast, turtles, or humans), before tackling gene recombination.During recombination, he explained, genes usually work in pairs, swapping material to lead to DNA repair and more robust genetic diversity. Every cell in the human body contains 23 pairs of chromosomes, and 22 of those pairs are matched. The 23rd in about 50 percent of people (that is, men) are not a matched pair but an XY pair. The Y chromosome is passed from father to son and contains the genes necessary for forming testicles, and therefore making sperm. Until Page’s laboratory learned differently, scientists believed that the Y chromosome, which has about 80 genes compared with the X’s 1,000 or so, did not pair-swap genetic material, and therefore was a weakened player.But Page and his colleagues discovered that the Y chromosome does swap genetic material. The twist is, it swaps with itself. The Y, Page’s lab learned, stores DNA as a palindrome that reads the same in either direction — like the name Otto, for example. “The palindromes on Y are spectacular,” Page said. “It has almost perfect left-arm-to-right-arm symmetry,” with only .06 percent divergence.One thing scientists knew was true was genes on the Y did not come in pairs, which would mean that Y chromosomes are very young, evolutionarily speaking, only about half a million years old. “Now all of a sudden we realized genes on Y come in pairs, just not from Mom and Dad, but on the arms of the palindrome.” The arms of the palindrome engage in “nonreciprocal recombination,” folding over on themselves to “overwrite” faulty genetic material.“This implies that the palindrome existed in the chimp/human ancestor 6 million years ago,” said Page, whose lab also sequenced the chimp Y chromosome and discovered that the Y has continued to evolve in the 6 million years since chimps and humans emerged from a common ancestor.Page and his colleagues also discovered that the Y chromosome may be linked to Turner syndrome in women, which is characterized by the lack of one sex chromosome, and can cause short stature, heart defects, and infertility due to ovarian malfunction. The syndrome may be the result of Y chromosome recombination gone awry, Page speculates, when the chromosome inadvertently becomes a palindrome with no gap in the center.Known as the centromere, the middle space between the two arms of the Y chromosome is key to its health. If two centromeres are inadvertently created, as they were on 18 of 60 patients studied who had low sperm production, there are anomalies of the Y chromosome, or discordance between chromosomal constitution and anatomy — that is, feminization. “It turns out these centromeres play a critical role in passing out one copy of each chromosome to each daughter cell,” said Page. “Ironically, the more Y you have, the more likely you’re a female.”last_img read more

Military spending in Latin America increased slightly in 2012: report

first_img Preparing for the World Cup Worldwide military expenditures in 2012 were estimated to have been $1.75 trillion (USD), a slight decrease from the amount of money countries spent on military programs in 2011, according to the Stockholm International Peace Research Institute (SIPRI). The decrease of 0.4 percent was the first time since 1998 that worldwide military expenditures decreased, according to SIPRI. Military spending increased slightly in Latin America. Nonetheless, the amount of money spent on military programs in 2012 – the most recent year for which such expenditures are available – was still one of the highest amounts ever spent, according to SIPRI. Military spending cuts in the United States, Australia, Canada, Japan, and a decrease in such expenditures by countries in Western and Central Europe accounted for much of the global drop in military spending, the report said. “The reductions were substantially offset by increased spending in Asia, Eastern Europe, the Middle East and North Africa, and Latin America. China, the second largest spender in 2012, increased its expenditure by 7.8 percent. Russia, the third largest spender, increased its expenditure by 16 percent,” according to the SIPRI report. The United States spent the most on military programs, $682 billion (USD), according to the report. The U.S. was followed by China, which spent $166 billion (USD) ; Russia, 90.7 billion (USD); the United Kingdom, $60.8 billion (USD), and Japan, $59.3 billion (USD). Among Latin American countries, only Brazil was in the top 15 in terms of expenditures. Brazil ranked 11th on the list. Brazil is also increasing security in preparation for hosting the 2014 FIFA World Cup. The Armed Forces and elite agents from the National Security Force of Brazil are working together to improve security for World Cup events. The games will take place from June 12 to July 13, 2014. About 600,000 foreign tourists are expected to go to Brazil to watch the games and take part in other World Cup events. The Special Secretariat for Security at Major Events (SESGE), which is part of the Ministry of Justice, is coordinating security preparations. Security officials are preparing to prevent terrorist attacks, violence by organized crime groups, and fan riots. Increased military spending in Paraguay, Brazil, and Mexico By Dialogo February 09, 2014center_img Military spending by countries in Latin America increased by 4.2 percent in 2012 compared to the previous year, according to the SIPRI report. Paraguay increased its military spending by 43 percent. Brazil increased military spending by $15 billion or 34 percent, and Mexico increased military expenditures by 10 percent, according to the SIPRI report and the Center for Strategic & International Studies. Mexico increased defense spending to fight international drug cartels. Some of these organizations, like the Sinaloa Cartel, also operate in Latin America. The Sinaloa Cartel is led by fugitive drug kingpin Joaquin “El Chapo” Guzman. In Brazil, spending on strategic programs, such as the development of submarines for the Navy, the modernization of its Air Force aircraft, and development of the transport aircraft KC-390 accounted for most of the increase in defense spending, according to the SIPRI report. Brazil’s military spending has increased dramatically since 2004, according to an analysis written by Santiago Pérez, a security analyst on Latin American military issues. “The federal government of Brazil stressed that military investments are in clear and uninterrupted expansion since 2004. The increase in absolute terms during that period was 480 percent, “ Pérez wrote. “ The expansion of defense spending responds to the logical necessity of properly defending the important natural resources of Brazil´s vast geography: drinking water, recently discovered oil under its seabed, the Amazon´s natural resources as well as other assets belonging to future generations should be properly protected,” Pérez wrote. Union of South American Nations Military spending by the members of the Union of South American Nations (UNASUR) nearly doubled between 2006 and 2010, according to the SIPRI report. UNASAR is comprised of Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela. Overall, South America continues to be one of the regions which spends the least on military programs, said SIPRI researcher Carina Solmirano told the Washington Office on Latin America (WOLA). “In absolute terms, South America continues to be one of the regions that spends the least on its militaries,” Solmirano said. “ To add some perspective, the $63.3 billion (USD) spent by South America is slightly above that spent by France alone, and represents only 4 percent of total global military expenditures.”last_img read more

Wellington Police Notes: Tuesday, May 24, 2016

first_imgWellington Police notes: Tuesday, May 24, 2016•1:11 a.m. Officers took a report of Suspicious Activity in the 2000 block N. H, Wellington.•8:13 a.m. Brian L. Marshall, 46, Wellington was issued a notice to appear for seatbelt violation.•8:15 a.m. Officers took a report of found bicycle in the 200 block W. Harvey, Wellington.•9 a.m. Officers took a report of found property in the 200 block N. Ash, Wellington.•9:25 a.m. Andrew N. Oldridge, 45, Wellington was issued a notice to appear for seatbelt violation.•9:30 a.m. Lincoln D. Crampton, 44, Caldwell, was issued a notice to appear for defective trailer lights.•10:30 a.m. Officers investigated making false information in the 200 block E. Harvey, Wellington.•10:50 a.m. Officers investigated a failure to report an accident by known subject in the 1200 block N. B, Wellington.•1:40 p.m. Officers investigated a theft of GPS in the 800 block E. 8th, Wellington. It was recovered.•1:45 p.m. Officers took a report of a verbal disturbance by known subject(s) in the 900 block W. 7th, Wellington.•4:36 p.m. Officers took a report of found wallets in the 400 block W. 16th, Wellington.•5:05 p.m. Kirk B. Howell, 46, South Haven, was issued a notice to appear for seatbelt volation.•5:20 p.m. Cari C. Martin, 31, Wellington was issued a notice to appear for seatbelt violation and no proof of insurance.•5:40 p.m. Cy C. Olivas, 25, South Haven, was issued a notice to appear for seatbelt violation.•6:10 p.m. Christopher R. Jesina, 45, Caldwell, was issued a notice to appear for seatbelt violation.•6:40 p.m. Officers investigated possession of depressants and possession of drug paraphernalia in the 100 block N. Washington, Wellington.•6:46 p.m. Sydney L. Palmer, 18, Wellington was issued a notice to appear for disobeyed stop sign.•6:54 p.m. Donald E. Schwab, 21, Wellington was arrested, charged and confined with possession of depressant and possession of drug paraphernalia.•6:58 p.m. Officers investigated a theft of license plate in the 500 block E. 16th, Wellington.•9:30 a.m. Officers took a report of suspicious activity in the 100 block W. Lincoln, Wellington.•10:05 p.m. Officers investigated criminal damage to property in the 100 block E. Sumner, Wellington.last_img read more