YSM Issue 86.3

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everyday Q&AQ&AIf a 300 million year trend continues, the Y chromosome may find itself on the path to extinction.The male sex chromosome andits X counterpart were initiallyidentical, but over the course ofmillennia, the Y has lost hundredsof genes. Some suggest that if thispattern persists, the Y chromosomemay completely disappearfrom the genomic map in five toten million years.Recent research, however, hassuggested otherwise. A studyby Dr. Jennifer Hughes at theWhitehead Institute comparedthe Y chromosome sequence ofthe chimpanzee, which differsfrom humans by six million yearsof evolution, to that of the rhesus monkey, which differs by 25million years. Surprisingly, the Y chromosome has undergone nochanges over the past six million years, and it has lost only onegene in 25 million years. In other words, it looks like gene loss hasQ&ADoes the Y Chromosome “Rot”?BY CARRIE CAOOriginally one of a pair of identical autosomes, the Ychromosome has since lost a large chunk of its genes.IMAGE COURTESY OF SCRIPPS COLLEGEWhat Causes Iridescence?reached an asymptote.Gene sequencing has also providedan additional insight: Whilethe Y chromosome’s genetic contenthas not changed in the past 25million years, it has lost large sectionsof repeated DNA sequences.Proponents of the Y chromosomedecay theory suggest that theremaining sequences will eventuallybe erased as well, but others believenatural selection has preserved thegenes for a reason, and that decayrepresents a kind of “purifying”force that will weed out all but themost essential genes.Whether or not the Y will eventually disappear remains a controversialquestion, but scientists do agree on one thing: We do notknow enough about the function of its genes to make a definiteprediction yet. For now, it seems like Y chromosome is here to stay.Iridescence is seen throughout nature in feathers, scales, and other objects, but how does it work?BY RENUSHA INDRALINGAMIf you have ever caught a glimpse of a shimmering peacockfeather, a butterfly wing, or even a soap bubble, you may havenoticed that the object seems to change color as you shift yourperspective — in fact, iridescence has played an inventive opticaltrick on you. What exactly creates this mesmerizing effect?Light travels in predictable patterns of waves, with rising crestsand falling troughs. Many colors found in nature are producedby pigmentation, which characterizes the absorption of certainwavelengths of light and the reflection of others. Iridescence,however, occurs when an object’s physical structure causes lightwaves to combine with one another, a phenomenon known asinterference. In constructive interference, light waves combineso that the crests and troughs line up to reinforce each other,increasing the vibrancy of the reflected color. Destructive interferenceoccurs when the crests and troughs cancel each other outto dim the color. Thus, as the observer’s viewing angle shifts, thecolors of the iridescent object change depending on the varyingdegrees of constructive and destructive interference.A variety of structural features interact with light to createiridescence. Some iridescent objects have multiple layers, such asa butterfly wing composed of layers of identically shaped scales.Light reflected from the top layer collides with light reflectedfrom the bottom layers to cause interference.While alluring, iridescence is more than just an optical curiosity.IMAGE COURTESY OF SANTOSH SHANMUGAAs viewers change their point of view in relation to thescarlet macaw’s iridescent feathers, the colors of thefeathers appear to change as well.In nature, it is used to recognize organisms of the same species,choose mates, and confuse and evade predators, proving it to bean extremely useful adaptation in the animal kingdom.2 Yale Scientific Magazine | April 2013 www.yalescientific.org
NEWS5 Letter from the Editor6 Novel Nano Biosensors DevelopedcontentsNovember 2013 / Vol. 86 / Issue No. 4ON THE COVER67Joan Steitz Receives the Grande MédailleQ&A with Physics Professor ReinaMaruyama7891011Q&A with Physics Professor MichelDevoretUncovering the Process of StarbirthNew Neural Imaging Methods DevelopedSmall Molecule Designed to Fight HeartIschemia54-Year-Old Mathematics ConjectureFinally ProvenFEATURES27283032333435363738Current EventsThe Impact of Sequestration on ResearchOceanographyAn Undiscovered World of OceanVirusesGeologyMega-Canyon Uncovered in GreenlandEnvironmentMythbusters: The Great Pacific GarbagePatchNeuroscienceDebunking Science: Near-DeathExperiencesUndergraduate ProfileJan Kolmas, TC '14Alumni ProfileYen-Yen Chang, SY '94, F&ES '01EcologyUrbanization Boosts Animal Brain SizeTriviaFive Things You Didn't Know aboutBlack HolesBook Reviews-Brilliant Blunders-The Eternal Darkness-Packing for Mars812The Future ofSpace ExplorationThe great unknownbeckons as moderntechnology and thespace industry’s rise toprominence offer a newparadigm in exploration.From asteroid mining toX PRIZE, rockets are justthe beginning.1518Astronomers Examine the Process of StarbirthYale Professor Héctor Arce and an international collaboration ofastronomers have used the Atacama Large Millimeter/submillimeterArray (ALMA) to obtain striking images of a protostar, providing a newglimpse into the dynamics of star formation.HIV & TB:Understandingthe EpidemicWhy is the TB/HIV dualepidemic so pervasive inSub-Saharan Africa? Dr.Richard Bucala's researchat the Yale School ofMedicine suggests thatgenetics holds the answer.TargetingDiabetes atits SourceA clinical trial led by Yaleprofessor Kevan Heroldmay lead to an effectivenew treatment for type 1diabetes.20Glia25IMAGE COURTESY OF ALMA/ESOIMAGE COURTESY OF COLON-RAMOS& Growth: Synapses in theDeveloping BrainIMAGES COURTESY Of BARAN SARACOptimizing Microstructures toEnhance DurabilityMore articles available online at www.yalescientific.orgwww.yalescientific.orgNovember 2013 | Yale Scientific Magazine 3
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Page 5 and 6: NEUROSCIENCEAcetylcholine receptors
Page 7 and 8: BY ANDREW DEVEAUENERGYEconomics Pro
Page 9 and 10: BY ELIZABETH HIMWICHASTRONOMYResear
Page 11 and 12: BY MAHBUBA TUSTYVIROLOGYCan Viruses
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YSM Issue 86.3

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