Uploaded August 2010 | Updated September 2026, 2 weeks ago
facebook.com/ScienceReason ... Calacademy: Are Men More Evolved Than Women? Comparing the differences in the Y chromosomes in chimps and humans has created quite a buzz.
---
Please SUBSCRIBE to Science & Reason:
• youtube.com/Best0fScience
• youtube.com/ScienceTV
• youtube.com/FFreeThinker
• youtube.com/RationalHumanism
---
Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content
The human Y chromosome began to evolve from an autosome hundreds of millions of years ago, acquiring a sex-determining function and undergoing a series of inversions that suppressed crossing over with the X chromosome. Little is known about the recent evolution of the Y chromosome because only the human Y chromosome has been fully sequenced. Prevailing theories hold that Y chromosomes evolve by gene loss, the pace of which slows over time, eventually leading to a paucity of genes, and stasis.
These theories have been buttressed by partial sequence data from newly emergent plant and animal Y chromosomes, but they have not been tested in older, highly evolved Y chromosomes such as that of humans. Here we finished sequencing of the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY. By comparing the MSYs of the two species we show that they differ radically in sequence structure and gene content, indicating rapid evolution during the past six million years.
The chimpanzee MSY contains twice as many massive palindromes as the human MSY, yet it has lost large fractions of the MSY protein-coding genes and gene families present in the last common ancestor. We suggest that the extraordinary divergence of the chimpanzee and human MSYs was driven by four synergistic factors: the prominent role of the MSY in sperm production, 'genetic hitchhiking' effects in the absence of meiotic crossing over, frequent ectopic recombination within the MSY, and species differences in mating behaviour. Although genetic decay may be the principal dynamic in the evolution of newly emergent Y chromosomes, wholesale renovation is the paramount theme in the continuing evolution of chimpanzee, human and perhaps other older MSYs.
• nature.com/nature/journal/v463/n7280/full/nature08700.html
---
Science in Action strives to make science accessible for everyone and discuss its relevance in our everyday lives. We bring you science news through media screens and live chats on the museum floor, this Science Today website, podcasts, and monthly Nightlife programming. We gather and disseminate content through our partners, local programs, other media and Academy staff. And you. Please feel free to comment and let us know what's important to you in the science world.
• calacademy.org/sciencetoday
.
facebook.com/ScienceReason ... Calacademy: Are Men More Evolved Than Women? Comparing the differences in the Y chromosomes in chimps and humans has created quite a buzz.
---
Please SUBSCRIBE to Science & Reason:
• youtube.com/Best0fScience
• youtube.com/ScienceTV
• youtube.com/FFreeThinker
• youtube.com/RationalHumanism
---
Chimpanzee and human Y chromosomes are remarkably divergent in structure and gene content
The human Y chromosome began to evolve from an autosome hundreds of millions of years ago, acquiring a sex-determining function and undergoing a series of inversions that suppressed crossing over with the X chromosome. Little is known about the recent evolution of the Y chromosome because only the human Y chromosome has been fully sequenced. Prevailing theories hold that Y chromosomes evolve by gene loss, the pace of which slows over time, eventually leading to a paucity of genes, and stasis.
These theories have been buttressed by partial sequence data from newly emergent plant and animal Y chromosomes, but they have not been tested in older, highly evolved Y chromosomes such as that of humans. Here we finished sequencing of the male-specific region of the Y chromosome (MSY) in our closest living relative, the chimpanzee, achieving levels of accuracy and completion previously reached for the human MSY. By comparing the MSYs of the two species we show that they differ radically in sequence structure and gene content, indicating rapid evolution during the past six million years.
The chimpanzee MSY contains twice as many massive palindromes as the human MSY, yet it has lost large fractions of the MSY protein-coding genes and gene families present in the last common ancestor. We suggest that the extraordinary divergence of the chimpanzee and human MSYs was driven by four synergistic factors: the prominent role of the MSY in sperm production, 'genetic hitchhiking' effects in the absence of meiotic crossing over, frequent ectopic recombination within the MSY, and species differences in mating behaviour. Although genetic decay may be the principal dynamic in the evolution of newly emergent Y chromosomes, wholesale renovation is the paramount theme in the continuing evolution of chimpanzee, human and perhaps other older MSYs.
• nature.com/nature/journal/v463/n7280/full/nature08700.html
---
Science in Action strives to make science accessible for everyone and discuss its relevance in our everyday lives. We bring you science news through media screens and live chats on the museum floor, this Science Today website, podcasts, and monthly Nightlife programming. We gather and disseminate content through our partners, local programs, other media and Academy staff. And you. Please feel free to comment and let us know what's important to you in the science world.
• calacademy.org/sciencetoday
.
![NASA Astronomy Pictures Of The Day [Week 3/2010]](https://i.ytimg.com/vi/sqYS7W-kgL8/mqdefault.jpg "NASA Astronomy Pictures Of The Day [Week 3/2010]
http://facebook.com/ScienceReason ... NASA Astronomy Pictures Of The Day [Week 3/2010].
Please SUBSCRIBE to Science & Reason:
• http://www.youtube.com/Best0fScience
• http://www.youtube.com/ScienceTV
• http://www.youtube.com/FFreeThinker
• http://www.youtube.com/RationalHumanism
► Eclipse over the Temple of Poseidon
The Moon moved to partly block the Sun for a few minutes last week as a partial solar eclipse became momentarily visible across part of planet Earth. In the above single exposure image, meticulous planning enabled careful photographers to capture the partially eclipsed Sun well posed just above the ancient ruins of the Temple of Poseidon in Sounio, Greece.
• http://antwrp.gsfc.nasa.gov/apod/ap100118.html
► Dust Sculptures in the Rosette Nebula
Noted for the common beauty of its overall shape, parts of the Rosette Nebula, also known as NGC 2237, show beauty even when viewed up close. Visible above are globules of dark dust and gas that are slowly being eroded away by the energetic light and winds by nearby massive stars. Left alone long enough, the molecular-cloud globules would likely form stars and planets. The Rosette Nebula spans about 50 light-years across and lies about 4,500 light-years away.
• http://antwrp.gsfc.nasa.gov/apod/ap091202.html
► Watch Jupiter Rotate
What would it be like to coast by Jupiter and watch it rotate? This was just the experience of the New Horizons spacecraft as it approached and flew by Jupiter. Visible above in the extensive atmosphere of the Solar Systems largest planet are bands and belts of light and dark clouds, as well as giant rotating storm systems seen as ovals. The robotic New Horizons spacecraft continues to speed toward the outer Solar System and has recently passed the halfway point between Earth and Pluto.
• http://antwrp.gsfc.nasa.gov/apod/astropix.html
► NGC 6992: Filaments of the Veil Nebula
Wisps like this are all that remain visible of a Milky Way star. About 7,500 years ago that star exploded in a supernova leaving the Veil Nebula, also known as the Cygnus Loop. At the time, the expanding cloud was likely as bright as a crescent Moon, remaining visible for weeks to people living at the dawn of recorded history. Today, the resulting supernova remnant has faded.
• http://antwrp.gsfc.nasa.gov/apod/ap091201.html
► Dark Sand Cascades on Mars
They might look like trees on Mars, but theyre not. Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost. The image was taken near the North Pole of Mars. At that time, dark sand on the interior of Martian sand dunes became more and more visible as the spring Sun melted the lighter carbon dioxide ice. When occurring near the top of a dune, dark sand may cascade down the dune leaving dark surface streaks streaks that might appear at first to be trees standing in front of the lighter regions, but cast no shadows.
• http://antwrp.gsfc.nasa.gov/apod/ap100119.html
► Eclipses in the Shade
Eclipses are everywhere in this shady scene. The picture was taken on the Indian Ocean atoll island of Ellaidhoo, Maldives, in January 2010, during the longest annular solar eclipse for the next 1,000 years. Tall palm trees provided the shade. Their many crossed leaves created gaps that acted like pinhole cameras, scattering recognizable eclipse images across the white sands of a tropical garden near the beach. From this idyllic location near the centerline of the Moons shadow track, the ring of fire or annular phase of the eclipse lasted about 10 minutes and 55 seconds.
• http://antwrp.gsfc.nasa.gov/apod/ap100123.html
► Dust and the NGC 7771 Group
Some 200 million light-years distant toward the constellation Pegasus, NGC 7771 is the large, edge-on spiral near center, about 75,000 light-years across, with two smaller galaxies just below it. Large spiral NGC 7769 is seen face-on to the right. Galaxies of the NGC 7771 group are interacting, making repeated close passages that will ultimately result in galaxy-galaxy mergers on a cosmic timescale.
• http://antwrp.gsfc.nasa.gov/apod/ap100121.html
► Millennium Annular Solar Eclipse
The Moons shadow raced across planet Earth on January 15. Observers within the central shadow track were able to witness an annular solar eclipse as the Moons apparent size was too small to completely cover the Sun. A visually dramatic ring of fire, the annular phase lasted up to 11 minutes and 8 seconds depending on location, the longest annular solar eclipse for the next 1,000 years.
• http://antwrp.gsfc.nasa.gov/apod/ap100122.html
► Himalayan Skyscape
Capella, alpha star of the constellation Auriga, rises over Mt. Everest in this panoramic view of the top of the world at night.
• http://antwrp.gsfc.nasa.gov/apod/ap091205.html
.")
![NASA Astronomy Pictures Of The Day [Week 6/2010]](https://i.ytimg.com/vi/z0d4aS1nY64/mqdefault.jpg "NASA Astronomy Pictures Of The Day [Week 6/2010]
http://facebook.com/ScienceReason ... NASA Astronomy Pictures of the Day [Week 6/2010]
Please SUBSCRIBE to Science & Reason:
• http://www.youtube.com/Best0fScience
• http://www.youtube.com/ScienceTV
• http://www.youtube.com/FFreeThinker
• http://www.youtube.com/RationalHumanism
► A Sun Halo Over Cambodia
Have you ever seen a halo around the Sun? This fairly common sight occurs when high thin clouds containing millions of tiny ice crystals cover much of the sky. Each ice crystal acts like a miniature lens. Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to ... http://antwrp.gsfc.nasa.gov/apod/ap100208.html
► Night Launch of the Space Shuttle Endeavour
Sometimes, the space shuttle launches at night. Pictured above, the space shuttle Endeavour lifted off in yesterdays early morning hours from Launch Pad 39A in Kennedy Space Center, Florida, USA, bound for the International Space Station (ISS). A night launch, useful for reaching the space station easily during some times of the year, frequently creates ... http://antwrp.gsfc.nasa.gov/apod/ap100209.html
► M51 Hubble Remix
The 51st entry in Charles Messiers famous catalog is perhaps the original spiral nebula - a large galaxy with a well defined spiral structure also cataloged as NGC 5194. Over 60,000 light-years across, M51s spiral arms and dust lanes clearly sweep in front of its companion galaxy (top), NGC 5195. Image data from the Hubbles Advanced Camera for Surveys has been reprocessed to ... http://antwrp.gsfc.nasa.gov/apod/ap091226.html
► Teide Sky Trails
The snow capped Teide volcano is reflected in a pool of water in this nearly symmetric night sky view from the Canary Island Tenerife. Bright north star Polaris stands above the peak in an exposure that also captures the brilliant trail of a polar orbiting Iridium satellite. Of course, with the camera fixed to a tripod, the stars themselves produce concentric trails in long exposures, a reflection of the Earths rotation around its axis ... http://antwrp.gsfc.nasa.gov/apod/ap100212.html
► Star Cluster M34
This pretty, open cluster of stars, M34, is about the size of the Full Moon on the sky. Easy to appreciate in small telescopes, it lies some 1,800 light-years away in the constellation Perseus. At that distance, M34 physically spans about 15 light-years. Formed at the same time from the same cloud of dust and gas, all the stars of M34 are about 200 million years young. But like any open star cluster ... http://antwrp.gsfc.nasa.gov/apod/ap100211.html
► A Force from Empty Space: The Casimir Effect
This tiny ball provides evidence that the universe will expand forever. Measuring slightly over one tenth of a millimeter, the ball moves toward a smooth plate in response to energy fluctuations in the vacuum of empty space. The attraction is known as the Casimir Effect, named for its discoverer, who, 50 years ago, was trying to understand why fluids like mayonnaise move so slowly ... http://antwrp.gsfc.nasa.gov/apod/ap061217.html
► Field of Rosette
What surrounds the florid Rosette nebula? To better picture this area of the sky, the famous flowery emission nebula on the far right has been captured recently in a deep and dramatic wide field image that features several other sky highlights. Designated NGC 2237, the center of the Rosette nebula is populated by the bright blue stars of open cluster NGC 2244, whose winds and energetic light are ... http://antwrp.gsfc.nasa.gov/apod/ap100214.html
► A Graceful Arc
The graceful arc of the Milky Way begins and ends at two mountain peaks in this solemn night sky panorama. The view was created from a 24 frame mosaic, with exposures tracking Earth and sky separately. In the final composition, northern Californias Mount Lassen was positioned at the left and Mount Shasta at the far right ... http://antwrp.gsfc.nasa.gov/apod/ap091225.html
► Sakurajima Volcano with Lightning
Why does a volcanic eruption sometimes create lightning? The Sakurajima volcano in southern Japan was caught erupting early last month. Magma bubbles so hot they glow shoot away as liquid rock bursts through the Earths surface from below. http://antwrp.gsfc.nasa.gov/apod/ap100210.html
► Waterway to Orbit
The 32nd shuttle mission to the International Space Station, STS-130, left planet Earth on February 8. Its early morning launch to orbit from Kennedy Space Centers pad 39A followed the long, graceful, eastward arc seen in this two minute time exposure ... http://antwrp.gsfc.nasa.gov/apod/ap100213.html
• Text authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP);
• A service of: ASD at NASA / GSFC & Michigan Tech. University
• http://antwrp.gsfc.nasa.gov/
.")
