Problem: Background: Richard Charles "Dick" Lewontin (born March 29, 1929) is an American evolutionary biologist, mathematician, geneticist, and social commentator. A leader in developing the mathematical basis of population genetics and evolutionary theory, he pioneered the application of techniques from molecular biology, such as gel electrophoresis, to questions of genetic variation and evolution. In a pair of seminal 1966 papers co-authored with J.L. Hubby in the journal Genetics, Lewontin helped set the stage for the modern field of molecular evolution. In 1979 he and Stephen Jay Gould introduced the term "spandrel" into evolutionary theory.
Context: Lewontin has worked in both theoretical and experimental population genetics. A hallmark of his work has been an interest in new technology. He was the first person to do a computer simulation of the behavior of a single gene locus (previous simulation work having been of models with multiple loci). In 1960 he and Ken-Ichi Kojima were the first population geneticists to give the equations for change of haplotype frequencies with interacting natural selection at two loci. This set off a wave of theoretical work on two-locus selection in the 1960s and 1970s. Their paper gave a theoretical derivation of the equilibria expected, and also investigated the dynamics of the model by computer iteration. Lewontin later introduced the D' measure of linkage disequilibrium. (He also introduced the term "linkage disequilibrium", about which many population geneticists have been unenthusiastic.)  In 1966, he and Jack Hubby published a paper that revolutionized population genetics. They used protein gel electrophoresis to survey dozens of loci in the fruit fly Drosophila pseudoobscura, and reported that a large fraction of the loci were polymorphic, and that at the average locus there was about a 15% chance that the individual was heterozygous. (Harry Harris reported similar results for humans at about the same time.) Previous work with gel electrophoresis had been reports of variation in single loci and did not give any sense of how common variation was.  Lewontin and Hubby's paper also discussed the possible explanation of the high levels of variability by either balancing selection or neutral mutation. Although they did not commit themselves to advocating neutrality, this was the first clear statement of the neutral theory for levels of variability within species. Lewontin and Hubby's paper had great impact--the discovery of high levels of molecular variability gave population geneticists ample material to work on, and gave them access to variation at single loci. The possible theoretical explanations of this rampant polymorphism became the focus of most population genetics work thereafter. Martin Kreitman was later to do a pioneering survey of population-level variability in DNA sequences while a Ph.D. student in Lewontin's lab.
Question: Are there any other interesting aspects about this article?
Answer: Lewontin and Hubby's paper also discussed the possible explanation of the high levels of variability by either balancing selection or neutral mutation.

Problem: Background: Dwayne Michael Carter Jr. was born on September 27, 1982, and grew up in the impoverished Hollygrove neighborhood of New Orleans, Louisiana. His mother, a cook, gave birth to him when she was 19 years old. His parents divorced when he was 2, and his father permanently abandoned the family. Although Wayne and Birdman have a father-son relationship and Birdman calls Carter his son, Wayne's biological father and namesake (Dwayne Carter) is still alive.
Context: Instead of a follow-up solo album, Lil Wayne reached his audience through a plethora of mixtapes and guest appearances on a variety of pop and hip-hop singles. Of his many mixtapes, Dedication 2 and Da Drought 3 received the most media exposure and critical review. Dedication 2, released in 2006, paired Lil Wayne with DJ Drama and contained the acclaimed socially conscious track "Georgia Bush", in which Lil Wayne critiqued former US president George W. Bush's response to the effects of Hurricane Katrina on the city of New Orleans. Da Drought 3 was released the following year and was available for free legal download. It contained Lil Wayne rapping over a variety of beats from recent hits by other musicians. A number of prominent hip-hop magazines such as XXL and Vibe covered the mixtape. Christian Hoard of Rolling Stone magazine considered the mixtapes Da Drought 3 and The Drought Is Over 2 (The Carter 3 Sessions) "among the best albums of 2007."  Despite no album release for two years, Lil Wayne appeared in numerous singles as a featured performer, including "Gimme That" by Chris Brown, "Make It Rain" by Fat Joe, "You" by Lloyd, and "We Takin' Over" by DJ Khaled (also featuring Akon, T.I., Rick Ross, Fat Joe, and Birdman), "Duffle Bag Boy" by Playaz Circle, "Sweetest Girl (Dollar Bill)" by Wyclef Jean (also featuring Akon), and the remix to "I'm So Hood" by DJ Khaled (also featuring T-Pain, Young Jeezy, Ludacris, Busta Rhymes, Big Boi, Fat Joe, Birdman, and Rick Ross). All these singles charted within the top 20 spots on the Billboard Hot 100, Hot Rap Tracks, and Hot R&B/Hip-Hop Songs charts. On Birdman's 2007 album 5 * Stunna, Lil Wayne appeared on the singles "100 Million" and "I Run This" among several other tracks. Wayne also appeared on tracks from albums Getback by Little Brother, American Gangster by Jay-Z, and Graduation by Kanye West and Insomniac by Enrique Iglesias. "Make it Rain", a Scott Storch production that peaked at number 13 on the Hot 100 and number two on the Hot Rap Tracks chart, was nominated for the Grammy Award for Best Rap Performance by a Duo or Group for 2008.  Vibe magazine ranked a list of 77 of Lil Wayne's songs from 2007 and ranked his verse in DJ Khaled's "We Takin Over" as his best of 2007, with "Dough Is What I Got" (a freestyle over the beat of Jay-Z's "Show Me What You Got") from Da Drought 3 the second song. At the end of 2007, an MTV poll selected Lil Wayne as "Hottest MC in the Game", The New Yorker magazine ranked him "Rapper of the Year", and GQ magazine named him "Workaholic of the Year". In 2008 he was named "Best MC" by Rolling Stone. Another article, built around Lil Wayne's 2007 mixtape work, cites his creative practice as an example of post performance creative practice.
Question: Did Lil Wayne collaborate on any other artist's songs during this time period?
Answer:
American Gangster by Jay-Z, and Graduation by Kanye West and Insomniac by Enrique Iglesias. "