input: 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.

Answer this question "What type of work was Richard involved in?"
output: both theoretical and experimental population genetics.

input: Messi's place in Argentina's Copa America Centenario squad was initially put in jeopardy when he sustained a back injury in a 1-0 friendly win over Honduras in a pre-Copa America warm-up match on 27 May 2016. It was later reported that he had suffered a deep bruise in his lumbar region, but that he would remain in Martino's squad for the tournament, although he was later left on the bench in Argentina's 2-1 opening win over defending champions Chile on 6 June due to concerns regarding his fitness. Although Messi was declared match-fit for his nation's second group match against Panama on 10 June, Martino left him on the bench once again; he replaced Augusto Fernandez in the 61st minute and subsequently scored a hat-trick in 19 minutes, also starting the play which led to Sergio Aguero's goal, as the match ended in a 5-0 victory, sealing Argentina's place in the quarter-finals of the competition; he was elected man of the match for his performance. On 18 June 2016, in the quarter-final of the Copa America against Venezuela, Messi produced another man of the match performance, assisting two goals and scoring another in a 4-1 victory, which enabled him to equal Gabriel Batistuta's national record of 54 goals in official international matches. This record was broken three days later when Messi scored in a 4-0 win in the semi-final of the Copa America against hosts the United States; he also assisted two goals during the match as Argentina sealed a place in the final of the competition for a second consecutive year, and was named man of the match once again. During a repeat of the previous year's final on 26 June, Argentina once again lost to Chile on penalties after a 0-0 deadlock, resulting in Messi's third consecutive defeat in a major tournament final with Argentina, and his fourth overall. After the match, Messi, who had missed his penalty in the shootout, announced his retirement from international football. Sources reported that other Argentine players - Sergio Aguero, Javier Mascherano, Gonzalo Higuain, Lucas Biglia, Ever Banega, Ezequiel Lavezzi and Angel Di Maria - could follow their captain in retiring from international football. Chile coach Juan Antonio Pizzi said after the match, "My generation can't compare him to Maradona that's for my generation, because of what Maradona did for Argentine football. But I think the best player ever played today here in the United States." Messi finished the tournament as the second highest scorer, behind Eduardo Vargas, with five goals, and was the highest assist provider with four assists, also winning more Man of the Match awards than any other player in the tournament (3); he was named to the team of the tournament for his performances, but missed out on the Golden Ball Award for best player, which went to Alexis Sanchez.

Answer this question "Did Martino's also retire?"
output:
other Argentine players - Sergio Aguero, Javier Mascherano, Gonzalo Higuain, Lucas Biglia, Ever Banega, Ezequiel Lavezzi and Angel Di Maria -