Mestizos in Mexico

In Mexico, the term Mestizo (lit. mixed) is used to refer to an ethnic group that can be defined by different criteria, namely a cultural criterion (the language spoken) or a more strict biological criterion. Because of this, estimates of the number of Mestizos in Mexico do vary. The meaning of the word Mestizo has changed over time. The word was originally used in the colonial era to refer to individuals who were of half-Spanish and half-indigenous American ancestry and it was one of the many extant castes used to classify individuals. While the caste system and racial classifications were officially abandoned once Mexico achieved its independence, the label mestizo was still used in academic circles: now to refer to all the people who were mixed race. It was in those academic circles that the "Mestizaje" or "Cosmic Race" ideology was created, the ideology asserted that Mestizos are the result of the mixing of all the races and that all of Mexico's population must become Mestizo so Mexico can finally achieve prosperity. After the Mexican Revolution the government, on its attempts to create an unified Mexican identity with no racial distinctions adopted and actively promoted the "Mestizaje" ideology, by 1930 racial identities other than "Indigenous" dissappeared from the Mexican census, however at an intitutional level all Mexicans who did not speak indigenous languages where now considered to be Mestizos, transforming what once was a racial identity into a cultural one.

In consequence, today people of very different phenotypes make up the Mestizo population in Mexico independently of whether they are mixed race or not. However, since the term carries a variety of socio-cultural, economic, racial, and genetic meanings, estimates of the Mexican Mestizo population vary widely. According to the Encyclopædia Britannica, which uses as base the results of the 1921 census, between one half and two thirds of the Mexican population is Mestizo. A culture-based estimate gives the percentage of Mestizos as high as 90%-93%. Paradoxically, the word Mestizo has long been dropped from popular Mexican vocabulary, with the word even having pejorative connotations, which further complicates attempts to quantify Mestizos via self-identification. In recent times, modern academics have challenged the Mestizaje concept, on the grounds that historical census data shows that marriages between people of different races were rare and that rather than ending racism, the ideology has incentivated it as it does negate the existence of the multiple ethnic groups and cultures that coexist in Mexico.

History
The exact date on which the term Mestizo and the caste system as a whole were introduced to Mexico is not known, however, the earliest surviving records that categorized people by different "qualities" (as castes were known in early colonial Mexico) are church birth and marriage records from the late 18th century. Back then there was an extensive caste system which assigned a different caste name for each possible racial combination, thus unlike definitions of "Mestizo" that would appear later, in these records "Mestizo" referred strictly to people who were of half Spanish and half indigenous ancestry. The same system is present in the first ever national population census of New Spain made in 1793, on which besides "Mestizo" the classification "castizo", "pardo", "mulatto", "zambo" etc. are present and are referred as a whole as "castes". After independence the caste system and racial censuses were legally abandoned which led to academics who reviewed and republished the census figures to refer to the "castes" collective simply as "Mestizos".

The aforementioned, new definition of “Mestizo” would be the one used in the 1921 census (the second nationwide census that included a comprehensive racial classification in Mexico‘s history). Made right after the consummation of the Mexican revolution, the social context on which this census was made makes it particularly unique, as the government of the time was in the process of rebuilding the country and was looking forward to uniting all Mexicans under a single national identity, the government found the identity it was looking for in the “mestizaje” or “cosmic race” ideology forged mainly by prominent academics and politicians José Vasconcelos and Manuel Gamio. The ideology asserted that Mexican Mestizos were the result of the mixing of all the races, obtaining the best qualities of each and that for Mexico to finally achieve prosperity all of the country’s population had to become Mestizo. By the 1930 census, the racial classifications of “White” and “Mestizo” disappeared, however implicitly all Mexicans who did not speak an indigenous language were now considered to be Mestizos. The government also implemented cultural policies designed to "help" indigenous peoples achieve the same level of progress as the Mestizo society, eventually assimilating indigenous peoples completely to mainstream Mexican culture, aiming to solve the "Indian problem" by transforming indigenous communities into Mestizo ones.

The institutional enforcement of the Mestizaje ideology would continue until after the first decade of the 21st century, when Mexico’s government begun to recognize at a degree the different ethnicities that conform Mexico’s non-indigenous population, likely due recommendations of Mexico’s modern academic circles, which nowadays criticize the ideology claiming that it delegitimizes racist practices in Mexico under the idea of “(Racism) Not existing here (Mexico), as everybody is Mestizo” said critics assert that the Mestizaje ideology thus, has cemented a terrain of resistance in regards to social, politic and academic mobility around the theme of race in Mexico as while at an institutional level a Mexican who is of Indigenous or African appareance and one who is of European appearance are of the same race, on everyday interactions they get inevitably perceived and treated differently by Mexico’s society. Other criticisms claim that the ideology couldn’t homogenize the different races that lived within Mexico because at its root, the ideology sought the “whitening” of Indigenous peoples and never the “indianization” of Whites or that it has accidentaly erased from history minority ethnic groups such as Afro-Mexicans. In general, the authors conclude that Mexico introducing a real racial classification and accepting itself as a multicultural country opposed to a monolithic Mestizo country would bring benefits to the Mexican society as a whole.

Outside of Mexico, the word "mestizo" is still used to refer to persons with mixed Indigenous and European ancestry. This usage does not conform to the modern Mexican usage of the word where a person of pure indigenous genetic heritage would be considered mestizo either by rejecting his indigenous culture or by not speaking an indigenous language, and a person with a very low or without any percentage of indigenous genetic heritage would be considered fully indigenous either by speaking an indigenous language or by identifying with a particular indigenous cultural heritage. In some regions of Mexico such as the Yucatán peninsula the word Mestizo is used to refer to the Maya-speaking populations living in traditional communities because during the caste war of the late 19th century those Maya who did not join the rebellion were classified as mestizos. In Chiapas, the term Ladino is used instead of Mestizo.

Overall, the term "Mestizo" is no longer in wide use in contemporary Mexican society, with its use being limited to social and cultural studies when referring to the non-indigenous part of the Mexican population. The word has somewhat pejorative connotations and most of the Mexican citizens who would be defined as mestizos in the sociological literature would probably self-identify as Mexicans, which complicate their quantification via self-identification. This is a direct contrast to ethno racial terms such as “Indian” “White” “Black” etc. who are still prominent in everyday social interactions in Mexico, it is not exactly known why this happened but is attributed to Mexicans simply favoring the use of “static” ethnic labels over “fluid” ones.

Population genetics
Mexicans who are biologically Mestizos are primarily of European and Native American ancestry. The third largest component is sub-Saharan African, a legacy of the slavery in New Spain (which saw the importation of some 100,000 -200,000 black slaves). However, geneticists theorize that in regions of Mexico that did not have any presence of slaves, traces of African ancestry might have come from Spanish colonists and not African slaves themselves, as said ancestry is of North African and Near East origin. Depending on the region, some may have small traces of Asian admixture due the thousands of Filipinos and Chinos (Asian slaves of diverse origin, not just Chinese) that arrived on the Nao de China. More recent Asian immigration (specifically Chinese) may help explain the comparatively high Asian contribution in Northwest Mexico (i.e., Sonora). The INMEGEN report also notes that on average, the largest genetic component of the self-identified Mestizo Mexicans is indigenous, while African and Asian genetic markers are diminishing with each generation and will continue to do so without new migration. For example, there were an estimated 600,000 Afromestizos or Mestizos of significant African descent at the end of the colonial period which roughly amounted to 10% of the population (Euromestizos and indomestizos were estimeted at 1,000,000 and 600,000 respectively) while as of 2015, the number of self identified Afro-Mexicans was 1.38 million (1.2% of the population).

The Mestizaje ideology, which has blurred the lines of race at an institutional level has also had a significative influence in genetic studies done in Mexico: As the criteria used in studies to determine if a Mexican is Mestizo or indigenous often lies in cultural traits such as the language spoken instead of racial self-identification or a phenotype-based selection there are studies on which populations who are considered to be Indigenous per virtue of the language spoken such as Nahua peoples from the state of Veracruz show a higher degree of European genetic admixture than the one populations considered to be Mestizo report in other studies. The opposite also happens, as there instances on which populations considered to be Mestizo show genetic frequencies very similar to continental European peoples in the case of Mestizos from the state of Durango or to European derived Americans in the case of Mestizos from the state of Jalisco.

Autosomal studies
Genetic research in the Mexican population is numerous and has yielded a myriad of different results, it is not rare that different genetic studies done in the same location vary greatly, clear examples of said variation are the city of Monterrey in the state of Nuevo León, which, depending of the study presents an average European ancestry ranging from 38% to 78%, and Mexico City, whose European admixture ranges from as little as 21% to 70%, reasons behind such variation may include the socioeconomic background of the analyzed samples as well as the criteria to recruit volunteers: some studies only analyze Mexicans who self-identify as Mestizos, others may classify the entire Mexican population as "mestizo", other studies may do both, such as the 2009 genetic study published by the INMEGEN (Mexico's National Institute of Genomic Medicine), which states that 93% of the Mexican population is Mestizo with the remaining being Amerindian, however for its study the institute only recruited people who explicitly self-identified as mestizos. Finally there are studies who avoid using any racial classification whatsoever, including in them any person that self-identifies as Mexican, these studies are the ones who usually report the highest European admixture for a given location.

Regardless of the criteria used all the autosomal DNA studies made coincide on there being a significant genetic variation depending on the region analyzed, with southern Mexico having prevalent Amerindian and small but higher than average African genetic contributions, the central region of Mexico showing a balance between Amerindian and European components, and the latter gradually increasing as one travels northwards and westwards, where European ancestry becomes the majority of the genetic contribution up until cities located at the Mexico-United States border, where studies suggest there is a significant resurgence of Amerindian and African admixture.

A 2006 study conducted by Mexico's National Institute of Genomic Medicine (INMEGEN), which genotyped 104 samples, reported that mestizo Mexicans are 59% European, 35% "Asian" (primarily Amerindian), and 5% Other.

Research conducted by the country's Instituto Nacional de Medicina Genómica (INMEGEN) has found that Mexico's Mestizo population is not uniform in its genetic composition, with there being significant regional variation. For example, mestizos of primarily European ancestry predominate in Sonora, while mestizos from the central region (Guanajuato and Zacatecas) have a more even split between indigenous and European. The highest African contribution in the twelve participating states (picked to be representative of the major regions of Mexico) was found in Guerrero and Veracruz, while the highest Asian contribution was found in Guerrero and Sonora.

A study made by the University College London which included the countries of Mexico, Brazil, Chile, Colombia and Brazil, and was made with collaboration of each countries' antrophology and genetics institutes reported the genetic ancestry of Mexican Mestizos was 56% Native American, 37% European and 5% African making Mexico, after Peru, the country with the highest Amerindian ancestry out of the five sample populations. Additionally, different phenotypical traits were analyzed, with the study determining that that the frequency of blond hair and light eyes in Mexicans was of 18.5% and 28.5% respectively, making Mexico also the country with the second highest frequency of blond hair in the study. The reason behind such discrepancy between phenotypical traits and genetic ancestry may lie in the low African contribution found within the Mexican population relative to Brazil and Colombia. In addition, the samples used in Mexico's case were highly unproportional, as the northern and western regions of Mexico contain 45% of Mexico's population, but no more than 10% of the samples used in the study came from the states located in these regions. For the most part, the rest of the samples hailed from Mexico City and southern Mexican states.

Additional studies suggests a tendency relating a higher European admixture with a higher socioeconomic status and a higher Amerindian ancestry with a lower socioeconomic status: a study made exclusively on low income Mestizos residing in Mexico City found the mean admixture to be  0.590, 0.348, and 0.062 for Amerindian, European and African respectively whereas the European admixture increased to an average of around 70% on mestizos belonging to a higher socioeconomical level. In 2011, an autosomal dna study was conducted in Mexico city, with 1,310 samples, showing the average proportion of Native American, European, and African ancestry for the population to be 64%, 32%, and 4% respectively. Additional autosomal dna studies conducted on people from Mexico city show a predominate Native American background, with Native American ancestry ranging from 61-69% in 5 different studies. The number of people sampled in these studies ranged from 66 to 984 people. One outlier study showed a predominate European background for mestizos of Mexico City, showing 57% European ancestry, 40% Native American ancestry, and 3% African ancestry. The sample population for this study however, was only 19 people.

MtDna and Y DNA studies
A 2012 study published by the Journal of Human Genetics Y chromosomes found the deep paternal ancestry of the Mexican  mestizo population to be predominately European (64.9%), followed by Amerindian (30.8%) and Asian (1.2%). The European Y chromosome was more prevalent in the north and west (66.7-95%) and Native American ancestry increased in the center and southeast (37-50%), the African ancestry was low and relatively homogeneous (0-8.8%). The states that participated in this study where Aguascalientes, Chiapas, Chihuahua, Durango, Guerrero, Jalisco, Oaxaca, Sinaloa, Veracruz and Yucatán. The largest amount of chromosomes found were identified as belonging to the haplogroups from Western Europe, East Europe and Eurasia, Siberia and the Americas and Northern Europe with relatively smaller traces of haplogroups from Central Asia, South-east Asia, South-central Asia, Western Asia, The Caucasus, North Africa, Near East, East Asia, North-east Asia, South-west Asia and the Middle East. Also a study published in 2011 on Mexican Mitochondrial DNA found that maternal ancestry was predominately Native American (85-90%), with a minority having European (5–7%) or African (3–5%) mtDNA.

An autosomal ancestry study performed on Mexico city reported that the European ancestry of Mexicans was 52% with the rest being Amerindian and a small African contribution, additionally maternal ancestry was analyzed, with 47% being of European origin. The only criteria for sample selection was that the volunteers self-identified as Mexicans.