4 Tips for Stand-Out Carnegie Mellon Essays

4 Tips for Stand-Out Carnegie Mellon Essays SAT / ACT Prep Online Guides and Tips Carnegie Mellon is ranked among the top 25 universities in the nation, so you’ll need to have an impressive application- with stand-out essays, of course!- in order to get admitted. Applicants must submita total of four Carnegie Mellon essays,three of which comprise the Carnegie Mellon supplement. Keep reading to learn what the current Carnegie Mellon essay prompts are, what topics you could write about, and what qualities make for a great Carnegie Mellon essay. Feature Image: Mathieu Thouvenin/Flickr What Are the Carnegie Mellon Essay Prompts? In addition to thepersonal statement you must write for the Common App (for which you get to select one out of seven possible prompts), Carnegie Mellon requires all applicants to submit three supplemental essays; theseessays make up the Carnegie Mellon Supplement. Applicants are not allowed to submit other supplemental materials with their applications, such as websites, artwork, or resumes. (Note that the only exception to this is ifyou’re applying to a school that requires additional materials, such as the School of Architecture.) Each essay may be up to 300 words long, making them a little shorter than your typical personal statement for college, which is usually around 500-600 words. So what are the Carnegie Mellon essay prompts? Let’s take a look: "When we‘re connected to others, we become better people," said Carnegie Mellon University‘s Randy Pausch, author of The Last Lecture. At Carnegie Mellon you‘ll have the opportunity to collaborate with a diverse community of scholars, artists and innovators. Given the students, faculty, staff and resources that have been available to you as a student, how have you collaborated with others, in or out of the classroom? Or, what lessons have you learned from working with others in the past, that might shape your experience in the future? Most students choose their intended major or area of study based on a passion or inspiration that’s developed over time- what passion or inspiration led you to choose this area of study? Consider your application as a whole. What do you personally want to emphasize about your application for the admission committee’s consideration? Highlight something that’s important to you or something you haven’t had a chance to share. Tell us, don’t show us (no websites please). As you can see, each Carnegie Mellon essay you must write will focus on something different about yourself.Specifically, you must explain the following in your essays: For Essay 1, how you have collaborated with others (on projects) For Essay 2, what you plan to major in and why For Essay 3, something you want to emphasize about yourself How should you write each Carnegie Mellon essay? We give you specific tips next. All Carnegie Mellon Essay Prompts, Analyzed In this section, we’ll go over the three Carnegie Mellon essay prompts in detail, giving you key tips so you can ensure your essays stand out from the rest of the crowd. Carnegie Mellon Essay 1: A Collaborative Experience "When we‘re connected to others, we become better people," said Carnegie Mellon University‘s Randy Pausch, author of The Last Lecture. At Carnegie Mellon you‘ll have the opportunity to collaborate with a diverse community of scholars, artists and innovators. Given the students, faculty, staff and resources that have been available to you as a student, how have you collaborated with others, in or out of the classroom? Or, what lessons have you learned from working with others in the past, that might shape your experience in the future? This first Carnegie Mellon essay prompt might appear complicated, but let’s try to break it down. What is this prompt really asking you to do? The first part of the prompt is explaining Carnegie Mellon’s diversity and ongoing commitment to fostering collaborative environments.Clearly, Carnegie Mellon strongly values teamwork and students' abilities to work well with others in order to produce interesting, successful projects. The second part of the prompt is the question (or rather the questions), which we can divide into three major ideas: Have you ever collaborated with others (such as students, teachers, etc.) on something? What did you learn about yourself from this experience? What kind of role do you think this experience play in your future? The first step to answering this prompt is to come up withone specific experience you want to write about.Here are some examples of potential topics: A group project you did for school, what role you played in that project, and what you gained from the experience. For example, did you delegate roles? Take charge to ensure everything was completed on time? Fix a major problem that almost compromised your project? A team sport you play or used to play. Was there a specific time you led others to success? Or maybe your team struggled to get along and you came up with a solution to get everyone to work together. A volunteer effort you worked on with others.Perhaps you assisted with a winter holiday food drive or raised money for a children's charity. What did this experience teach you about collaboration? A group task you must do for a part-time job. For instance, maybe you work at a video game store and must take turns with your co-workers in stocking new games and helping customers. Has this experience had an effect on how you approach or view teamwork? This is a great essay in which toemphasize your leadership skills if you assumed some sort of leadership role in a group project or activity. If you didn’t take on a leadership role, that’s totally OK- just focus on what role you did play on the team you were part of and explain what this experience taught you about working together to accomplish a shared goal. Another thing to remember is to be as specific as possible.Don’t be afraid to use people’s names and delve into your feelings about the project or activity you did with others. For example, maybe the experience you're writing about was a challenge in the beginning- maybe your group couldn't agree on a science project to do for the school science fair. However, onceyou had everyone write down their project ideas and share them with one another, your group was at last able to decide on a project idea. As a final tip for this essay prompt,be clear about how this experience has affected you and might impact your future (at Carnegie Mellon).Maybe that experience working on the group science project taught you the importance of giving everyone a say in the brainstorming process, so you’ll ensure this happens with any group projects you work on at Carnegie Mellon, too. Carnegie Mellon Essay 2: Your Intended Major Most students choose their intended major or area of study based on a passion or inspiration that’s developed over time- what passion or inspiration led you to choose this area of study? Though it might look a little wordy, all this Carnegie Mellon essay prompt is really asking is, "Why this major?"More specifically,this prompt wants you to relate the intellectual path you've taken by explaining the experiences, people, and/or events that have led you to want to major in this particular field. By far the most effective way to answer this prompt is to tell a compelling story about how you came to be interested in your intended major.Think about the most important moments from your life that showcase your love of what you want to study, and then write about those. For example, say you plan to major in musical composition.You could start off by recounting the first time you tried to write a piece of music on your family’s piano and how hard it was. However, you really enjoyed the process of creating something new. This prompted you toenroll in weekly piano lessons; you also continued to compose piano pieces in your spare time. As a sophomore, you decided to enteryour school’s talent show and ended up winning with a musical piece you’d composed. While you don’t need to stick to chronological order, using this organization ensures your essay is easy to follow and clearly illustrates how you progressed from someone who knew nothing about the field to someone now highly devoted to it. In addition, be sure to focus on not only how you became interested in your major but also how this journey of discovering your passion has affected you and your goals.For example, perhaps you want to major in architecture because you hope to use your skills to encourage eco-friendly living and therefore combat the effects of climate change. It’s also a good idea to mention, explicitly or implicitly, how Carnegie Mellon will help you accomplish your goals in your intended field.You could talk briefly about a particular faculty member in your field whom you hope to work with, an expensive piece of equipment offered at Carnegie Mellon, or specific professional opportunities available to students. Finally, be careful not to exaggerate.Don’t say you suddenly developed an interest in literature after reading The Great Gatsby for English class if you actually loathed the book or had a passion for literature well before then. It’s OK if there wasn't one single moment in your life that made you realize this major was the right one for you.Instead of acting as though some particular incident was more significant than it actually was, just focus on the overall journey you took to get to the point you’re at now- that is, the major you’ve chosen to pursue. What defines you? Carnegie Mellon Essay 3: Something Important About You Consider your application as a whole. What do you personally want to emphasize about your application for the admission committee’s consideration? Highlight something that’s important to you or something you haven’t had a chance to share. Tell us, don’t show us (no websites please). This essay prompt is the most open ended of the three and a great opportunity to really dig into any important attributes of yourself that you feel you didn’t get to write enough about or at all in other parts of your application. Did you write about something in another essay, such as the one you wrote for the Common App, that you wish to talk about more here?Do you want to write about something that’s important to you and that you haven’t had a chance to elaborate on yet? Your topics are pretty endless here- just make sure whatever you write about for this essay is revealing something important that you think the admissions committee should know about you. This could be a specific personality trait- maybe you want to emphasize your leadership skills by talking about your role as team leader at the local youth club- or something about your life that’s had a major impact on how you see yourself and your future. Here are some topics you could write about (but don’t feel limited by these suggestions!): A specific incident that holds importance for you, and what it taught you about your academic and/or professional interests, your goals, your personality, etc. Someone you know who has impacted you in a significant way, and how that person has specifically influenced your interests and/or goals An explanation for something that negatively impacted your grades or another part of your application- for example, perhapsyou spent a lot of time taking care of a sick relative during your sophomore year of high school, which caused your grades to dip slightly A particular interest, passion, hobby, or skill you have, and what you've gained, either intellectually or emotionally, from it Once again,don’t try to write about what you think the CMU admissions committee wants to read- be honest about what’s important to you and why.If you volunteered somewhere a few times but didn’t enjoy it or gain anything valuable from it, do not write about it here! Similarly,don’t be afraid to focus on something seemingly mundane. Just besure you’re using the topic you choose- even if it’s pretty commonplace- to ultimately reveal something important about you. So, no, it'sprobably not a good idea to write about how you spend hours on Instagram every day, since this hobby isn’t really revealing anything significant about you, your goals, or your personal growth. 2 Real Carnegie Mellon Essay Examples + Analysis In order to write a great Carnegie Mellon essay, it helps to see what kinds of essays actually got applicants accepted to this prestigious university. Here, we give youtwo real Carnegie Mellon essay examples we found online and explain what makes them successful. Note: This year’s Carnegie Mellon essay prompts are new, so the following essays are in response to older prompts with different word limits. Despite these differences, being able to see the kinds of stories successful applicants have told should give you a clear sense of what topics, details, and styles might work well for your own Carnegie Mellon admissions essays! Carnegie Mellon Essay Example 1 This first of the two Carnegie Mellon essay examples comes from the college essays website Essays That Worked.The essay is quite long- more than 650 words!- and was written in response to the following (old) supplemental Carnegie Mellon essay prompt: Why Carnegie Mellon University? And now here's the essay: As a child who hid behind her parents and never uttered a word whenever strangers were near, I was no stranger to people deeming me shy. As I got older, however, I found my voice more comfortably through music, through art, and through writing. Playing Mozart’s Violin Concerto in the Kennedy Center, for instance, unleashed a swell of emotions through the intricate art of storytelling with my violin. I was drawn to writing stories and sharing ideas with my peers, starting my editor career in fifth grade. Five years later, I co-founded my high school’s literary magazine, Muses, which provides a platform for all voices while fostering connections among students. I was twelve years old when an HTML class through Johns Hopkins University’s Center for Talented Youth program introduced me to a modern language of communication: computers and the internet. Falling in love with coding and website design, I utilized my newfound knowledge to design a website for my National History Day project, which won the school competition. In high school, I joined programming club, took the rigorous computer science classes, and designed Muses’ website. This year, I created a conceptual online boutique store, which won first place in Maryland Future Business Leader Association’s E-business competitive event. In the summer of 2016, I interned in an NCI melanoma research lab. This experience completely changed how I viewed the importance of technology to modern communication. We had obtained genotypes from thousands of melanoma patients and controls, but a new question arose: how could we extract the useful information from a massive data file, akin to finding a needle in a haystack? Under the guidance of a bioinformatician, I performed an association test between melanoma associated variants and survival outcome to identify the risk loci that might affect patient survival. Catering to the needs of the scientists, I wrote an app by R code that organizes and manages melanoma genotype information; extracting the information of a particular genotype and its association with melanoma was now a couple clicks away. From this work, I learned how to translate large data into solutions, while using the correct data format and data structure. I realized that modern technology not only helps us commu nicate more efficiently, but also provides a system upon which we can solve global problems. With a strong background in computer science and communications, I hope to incorporate both into a future career of building data systems, conducting research, and consulting for organizations that serve underrepresented citizens. One project I want to tackle is the modification of social media algorithms so that media created by minorities and/or for minorities will appear on users’ radars. The algorithm would analyze the user’s demographics and deliver news relevant to those traits, such as discoveries about Asian health issues showing up on Asian users’ feeds. Carnegie Mellon’s encouragement of interdisciplinary studies under the Information Systems major would allow me to accomplish this and so much more. As someone who attacks calculus and creative writing with equal enthusiasm, IS’ objective of providing students with a broad background in the humanities and sciences is very appealing. As someone who learned to work as a team in a research lab , I believe CMU’s emphasis on collaboration and student innovation would push me to further improve my teamwork and problem-solving skills. In particular, I hope to take advantage of CMU’s Technology Consulting in the Global Community program, receiving guidance from both CMU’s renowned faculty and international technology experts. To that end, the Social and Decision Sciences major, my second choice, would also prepare me to utilize similar decision-making and analysis skills to solve social problems. We live in a world where communication through technology connects communities across the globe, more so than ever before. The future of exploration and innovation requires us to develop efficient ways of communication- we need a combination of scientific expertise and knowledge grounded in the humanities to accurately convey ideas, solve problems, and make the planet a better home for us all. An education at Carnegie Mellon would propel me in this endeavor. Here’s why this Carnegie Mellon essay works so well: It has an honest, compelling narrative that flows well. This applicant begins by explaining how they've always been considered shy yet how, through various endeavors in fields such as writing, communication, and technology, they've managed to transcend this assumption. This story is raw and honest, and it highlights the applicant's most notable accomplishments in an appropriate and relevant manner. It’s extremely specific. The applicant uses concrete details to explain their background and why Carnegie Mellon is an ideal fit for their goals and interests. In addition, the essay makes note of specific qualities of CMU, from its "encouragement of interdisciplinary studies" to its Technology Consulting in the Global Community program, giving us a clear indication of why the applicant is so interested in attending this school. Concrete details are essential for a good Carnegie Mellon essay. Carnegie Mellon Essay Example 2 This second Carnegie Mellon essay example comes from the website Free Test Prep (now called BWS Education Consulting) and is, like the essay above, quite long at about 600 words- that’s double the current word limit. It was written in response to the following (old) Carnegie Mellon essay prompt: Please submit a one-page, single-spaced essay that explains why you have chosen Carnegie Mellon and your particular major(s), department(s) or program(s). This essay should include the reasons why you’ve chosen the major(s), any goals or relevant work plans and any other information you would like us to know. If you are applying to more than one college or program, please mention each college or program you are applying to. Because our admission committees review applicants by college and programs, your essay can impact our final decision. Please do not exceed one page for this essay. Here is the essay: What would be best for me? I spent a lot of time trying to find colleges to apply to and Carnegie Mellon made the list. I believe it would be essential for me to attend a research university. I want to be able to know that what I am working on (research, experiments, etc.) is current, ground-breaking, game-changing. I want to feel that what I’m doing matters. I’ve spent years in elementary and middle school only to discover that my achievements (and no, I don’t only mean my perfect attendance awards) did not grandfather in for the rest of my academic life. High school did not care whether I attended elementary regularly or about any of my pre-secondary school achievements. College applications only want to know what I have done throughout these past four years. I feel that Carnegie Mellon will provide me with an environment that will let me grow and change as the world is growing and changing. What I do here will matter and carry on to whatever graduate school I may be at or whatever career path I choose to tread. In the International Baccalaureate (IB) program, one can choose from several Higher Level (HL) courses to fulfill the three required. My campus chose to make English and History mandatory HL’s. I chose to take HL Psychology as my third. This focused two-year class has revealed my interest in psychology as a lifelong study and future career. I have always been interested in human behaviors, how and why people make their decisions, how both internal and external factors can and do influence everyday life. As this class has progressed, I have found myself enjoying these studies more and more. I have been very successful in this class and want to apply the knowledge and skills I have learned to real-world situations. Psychology HL requires students to complete two experiments, one in our junior year and one in our senior year. Additionally, we complete an Internal Assessment (IA) of the experiment done early senior year. My group had to create an experiment based on three past studies and go through the process of analyzing the validity of our results after performing the experiment on student participants. We tested the effect of researcher expectations on participant performance, using the studies of Rosenthal and Jacobson (1966); Stangor, Carr, and Kiang (1998); and Crisson, Seta, and Seta (1989). The objective of this project was to reflect on what we did, how it was done, and what could have been improved on. Although we had to accept our null hypothesis, that researcher expectations had little or no effect on participant performance, we were able to understand what went askew and know what to correct so we could improve the performance, given the opportunity to do it again. I found performi ng the experiments live exciting; I had to be wary of creating bias or unconsciously affecting others. It made me become more analytical; more understanding of the fact that many factors can influence behavior and more understanding of my own role in affecting others. I’m applying to Carnegie Mellon into the Dietrich College of Humanities and Social Sciences. I believe that my two years in HL Psychology have prepared me well for whatever is demanded of me. I hope to take advantage of all the programs available at Dietrich College, such as the HSS Academic Advisory Center and HSS Career Connections. I expect to thrive during these next four years, prepared enough to head on into graduate school for a PhD in Psychology. Here’s why this Carnegie Mellon essay works so well: It’s tightly focused. This essay centers on the applicant's desire to study psychology, a topic that is made clear quickly and acts as the focal point throughout the essay. We learn that the applicant initially developed an interest in psychology through their high school's IB Program and that they intend to eventually get a PhD in the field. It goes into significant detail about a specific incident. In order to showcase their passion for psychology, this applicant wrote a detailed description of an experiment they conducted, what they learned from it, and how this knowledge will allow them to succeed at CMU. 4 Tips for a Great Carnegie Mellon Essay As you now know, you’ll need to write three essays for the Carnegie Mellon supplement.Here are some general tips to keep in mind as you begin to work on each Carnegie Mellon essay. #1: Use Highly Specific Details Don’t rely on catch-all phrases to get your points across in your essays. Instead, try to think of real, concrete examples you can use. Specific details will make each Carnegie Mellon essay you write (and your application as a whole!) stand apart from others; it also proves to the admissions committee that you know what kinds of opportunities are available to you at Carnegie Mellon. #2: Avoid Exaggeration- Be Yourself! Many students think they need to write about topics that sound "impressive," but this isn’t actually what admissions committees want.What they really want is to learn more about who you are, what you sound like naturally (on paper, of course), and what you value in life. This is why it’s so important for you to clearly channel your voice in your writing.For example, it’s OK to tell a joke or focus on a lighthearted topic if you would describe yourself as a comedian. Just make sure that, no matter what kind of topic you choose or how you write,you're ultimately making a bigger, important point about yourself- one that ideally emphasizes essential facets of your personality, your experiences, and/or your ambitions. #3: Don’t Repeat Anything You’ve Written for Your Common App Essay Carnegie Mellon requires all applicants to submit the Common App essay in addition to the three essays described above, so you’ll want to ensurethere’s not too much overlap between them. While it’s OK to elaborate on a specific topic or point that you briefly mentioned in another essay, don’t end up writing about the same experience more than once. The point of these essays is to showcase various aspects of your personality and life, and you won’t succeed if all you’re doing is repeating yourself in each Carnegie Mellon essay! Repetition: good for making pretty patterns, bad for college essays. #4: Edit, Polish, and Proofread Our final tip is to take a lot of time to edit, polish, and proofread each Carnegie Mellon essay you write.Look over each essay multiple times to catch typos and other technical errors, such as grammatical problems, and spelling mistakes. You should also be on the lookout for the following problems: Any inconsistencies in style, tone, voice, tense, etc. Any areas that are unclear, vague, or awkwardly worded or placed Any irrelevant details or descriptions that don’t add anything important Once you've edited and changed your essays a few times, give them to someone you trust, such as a teacher, mentor, or parent, and have that person offer feedback on how you could improve your writing. Here are some key questions to ask this person to think about as they edit your essay: Is the topic/theme effective and appropriate for a college essay? Does the essay sound as though you wrote it (and not someone else)? Does the voice sound like your authentic voice? Does the overall organization make sense? Is there a story, and does it flow well? Does the structure successfully get the main point across? Are the details specific and relevant? With all these tips in mind, you should definitely be able to write a great Carnegie Mellon essay! What’s Next? You'll need to use the Common App if you're applying to Carnegie Mellon. Get tips on how to write a great Common App essay with our expert guide. Thinking of applying to other great schools likePrinceton, Brown, or Columbia? Then be sure to check out our guides to learn how you can write amazing essays for these schools' supplements. Learn more about Carnegie Mellon's admission requirements by visiting its school page in our extensive database. Want to write the perfect college application essay? Get professional help from PrepScholar. Your dedicated PrepScholar Admissions counselor will craft your perfect college essay, from the ground up. We'll learn your background and interests, brainstorm essay topics, and walk you through the essay drafting process, step-by-step. At the end, you'll have a unique essay that you'll proudly submit to your top choice colleges. Don't leave your college application to chance. Find out more about PrepScholar Admissions now:

History of the Domestication of Sunflowers

History of the Domestication of Sunflowers Sunflowers (Helianthus spp.) are plants native to the American continents, and one of four seed-bearing species known to have been domesticated in eastern North America. The others are squash [Cucurbita pepo var oviferia], marshelder [Iva annua], and chenopod [Chenopodium berlandieri]). Prehistorically, people used sunflower seeds for ornamental and ceremonial use, as well as for food and flavoring. Prior to domestication, wild sunflowers were spread throughout the North and Central American continents. Wild sunflower seeds have been found in numerous locations in eastern North America; the earliest so far is within the American Archaic levels of the Koster site, as early as 8500 calendar years BP (cal BP); when it was precisely domesticated, is difficult to establish, but at least 3,000 cal BP. Identifying Domesticated Versions Archaeological evidence accepted for recognizing the domesticated form of sunflowers (Helianthus annuus L.) is the increase in the average mean length and width of achenethe pod that contains the sunflower seed; and since Charles Heisers comprehensive studies in the 1950s, the established reasonable minimum length for determining whether a particular achene is domesticated has been 7.0 millimeters (about a third of an inch). Unfortunately, that is problematic: because many sunflower seeds and achenes were recovered in the charred (carbonized) state, and carbonization can, and in fact often does, shrink the achene. In addition, the accidental hybridization of wild and domestic formsalso results in smaller sized domestic achenes. Standards to correct for carbonized seeds developed from experimental archaeology on sunflowers from DeSoto National Wildlife Refuge found that carbonized achenes exhibited an average of 12.1% reduction in size after being carbonized. Based on that, Smith (2014) proposed scholars use multipliers of about 1.35-1.61 to estimate the original size. In other words, measurements of carbonized sunflower achenes should be multiplied by 1.35-1.61, and if the majority of the achenes falls over 7 mm, you can reasonably surmise that the seeds are from a domesticated plant. Alternatively, Heiser suggested that a better measure might be the heads (disks) of sunflowers. Domesticated sunflower disks are significantly larger than wild ones, but,  unfortunately, only about two dozen partial or complete heads have been identified archaeologically. Earliest Domestication of Sunflowers The main site of domestication for sunflower appears to have been located in the eastern North American woodlands, from several dry caves and rock shelters of the central and eastern United States. The firmest evidence is from a large assemblage from the Marble Bluff site in the Arkansas Ozarks, securely dated to 3000 cal BP. Other early sites with smaller assemblages but potentially domesticated seeds include Newt Kash Hollow rock shelter in eastern Kentucky (3300 cal BP); Riverton, Eastern Illinois (3600-3800 cal BP); Napoleon Hollow, central Illinois (4400 cal BP); the Hayes site in central Tennessee (4840 cal BP); and Koster in Illinois (ca 6000 cal BP). In sites more recent than 3000 cal BP, domesticate sunflowers are frequent occurrences. Early domesticated sunflower seed and achene was reported from the San Andrà ©s site in Tabasco, Mexico, direct dated by AMS to between 4500-4800 cal BP. However, recent genetic research has shown that all modern domestic sunflowers developed from the wild eastern North American species. Some scholars have argued that the San Andres specimens may not be sunflower  but if they are, they represent a second, later domestication event that failed. Sources Crites, Gary D. 1993 Domesticated sunflower in Fifth Millennium B.P temporal context: New evidence from middle Tennessee. American Antiquity 58(1):146-148. Damiano, Fabrizio, Luigi R. Ceci, Luisa Siculella, and Raffaele Gallerani 2002 Transcription of two sunflower (Helianthus annuus L.) mitochondrial tRNA genes having different genetic origins. Gene  286(1):25-32. Heiser Jr. CB. 1955. The origin and development of the cultivated sunflower. The American Biology Teacher 17(5):161-167. Lentz, David L., et al. 2008 Sunflower (Helianthus annuus L.) as a pre-Columbian domesticate in Mexico. Proceedings of the National Academy of Sciences 105(17):6232-6237. Lentz D, Pohl M, Pope K, and Wyatt A. 2001. Prehistoric sunflower (Helianthus Annuus L.) domestication in Mexico. Economic Botany  55(3):370-376. Piperno, Dolores R. 2001 On Maize and the Sunflower. Science  292(5525):2260-2261. Pope, Kevin O., et al. 2001 Origin and Environmental Setting of Ancient Agriculture in the Lowlands of Mesoamerica. Science 292(5520):1370-1373. Smith BD. 2014. The domestication of Helianthus annuus L. (sunflower). Vegetation History and Archaeobotany 23(1):57-74. doi: 10.1007/s00334-013-0393-3 Smith, Bruce D. 2006 Eastern North America as an independent center of plant domestication. Proceedings of the National Academy of Sciences 103(33):12223-12228.