Are humans really so alike? Comparisons of humans, emperor penguins, and chimpanzees. Which of these pairs of animals do you think has the most variation within their species? Take a look at the photos on the left. There are three pairs of two members of the same species. Which pair do you think is more genetically similar? Would you guess Kanye West and Taylor Swift are more alike, or two penguins?
What about Kanye and Taylor versus two chimps? It may surprise you to learn that penguins have twice as much genetic variation as humans do.
And this subspecies of chimp has more genetic variation than all the humans on earth. Humans haven't been around as long as other animals.
We haven't had enough time to develop much variation in our DNA. Humans also migrate and reproduce a lot. Different groups of humans are never apart long enough for genetic differences to add up. Human DNA is too similar to split us into subspecies or races. So we can't use biology to sort people into groups like we can with animals.
Even though our DNA is similar, humans look very different from each other. But the traits we use to guess someone's race don't always work well. Think about skin color. There aren't just a few colors: there are more shades than you can ever count.
The traits we use are also independent of each other. No matter which traits we use, there is no good way to group humans using appearance or DNA. Instead, everyone groups people into races based on the traits they think are most important.
The way we categorize people into races changes over time, too. The median white man of the, on average, tallest racial group among U. The distribution of variation in stature within human populations is broad and very different from that seen in dog breeds. The height distributions of men in the U. Both groups overlap even more substantially with black men. It is also worth noting that the difference in median height between men and women of a single U.
Consider the tallest Manute Bol at cm or 91 in. While they represent extremes of the human male height distribution, Bol is only 1.
In contrast, dog breed differences in stature are far greater than what is observed across U. The median shoulder height in Great Danes 76 cm, 30 in. When scaled to human height, this would be equivalent to a difference of Years of breeding to divergent standards combined with low genetic diversity has resulted in limited and non-overlapping height variation for many breeds Sutter et al. Height, like most traits in humans, is extremely complex, meaning it is regulated by a large number of genes the vast majority of which show nearly identical variation across all human populations plus environmental factors.
It takes more than genetic loci to explain only half of human height variation Wood et al. Considering dogs, one haplotype in IGF1 explains These differences between humans and dogs in the genetic complexity and the diversity of their traits are due to the distinct impact of artificial selection on dogs.
Human genetic variation has been shaped over many generations by relatively weak natural selection on most traits, including height. For example, natural selection on height may occur in certain climate conditions where being taller or shorter may amount to some thermoregulatory or metabolic boost to reproductive success.
However, even in populations where height or skin color or any other such variable trait is under selection, the majority of individuals across the phenotypic spectrum will still reproduce and pass their genes on to the next generation. As a result, human populations are genetically very similar to one another with overlapping phenotypes. In contrast, modern purebred dogs exist almost entirely due to artificial selection; their mating is controlled by humans to produce offspring with desired traits.
To do this, animals with rare genetic mutations, like those with the dwarf variant of IGF1 , are bred together for several generations, acting against the natural accumulation of genetic variation i. Dog breeds seem to be so distinct from one another in many conspicuous traits because, relative to human groups, they are.
This is true in terms of the extreme differences in physical traits seen between dog breeds, whereas U. There are clear and important biological differences between the categories of U.
But such criticisms only illustrate the subjective, sociocultural construction of the categories humans define as race. While definitions and perceptions of racial categories vary person to person, culture to culture, and throughout time, dog breeds are strictly defined in their breed standards.
For example, here is the Portuguese Water Dog Fig. The Portuguese Water Dog is a swimmer and diver of exceptional ability and stamina, who aided his master at sea by retrieving broken nets, herding schools of fish, and carrying messages between boats and to shore. He is a loyal companion and alert guard. This highly intelligent utilitarian breed is distinguished by two coat types, either curly or wavy; an impressive head of considerable breadth and well proportioned mass; a ruggedly built, well-knit body; and a powerful, thickly based tail, carried gallantly or used purposefully as a rudder.
The Portuguese Water Dog provides an indelible impression of strength, spirit, and soundness. All AKC breed standards include physical and behavioral traits, and describe an ideal condition. For physician and anatomist J. In that piece the authors challenge researchers to consider a paradox first noted by Dobzhansky : while race can be a tool to elucidate human genetic diversity, it is a blunt implement that does a poor job of explaining actual relationships between ancestry and genetics.
Yudell and colleagues charge researchers and scientific societies to think critically about, and to justify their use of, particular categories to describe human diversity. Careful consideration of the terminology used in biomedical studies forces both scientists and the public to more clearly understand the questions being asked and the variables used to do so.
The goal is not to ignore patterns of human biological or genetic diversity, but rather to identify new methods to explore these patterns that do not reproduce the harm caused when human biological variation is treated as a mere synonym for racial categories built on the hierarchical organization of people. In resisting the scientifically historical idea of race where separate human groups were ranked hierarchically, C. Emphasizing the sociocultural construction of race in no way diminishes the reality of race as a powerful phenomenon.
Rather, racial experience is emphasized as an embodied experience that is as real and as valid as biological variation. Yudell et al. Such research is important to understand how structural inequities and discrimination produce health disparities in socioculturally defined groups. According to a survey by Wagner et al. Here is a glance at the orientation within that anthropological majority:.
To a first approximation, then, we mean that, unlike a naively regarded fact of nature, which is presumably there to be observed and transparently understood, race is a product of history; and although it is often associated with variation in biological form, it is inherited according to cultural, not biological, rules. It can only be grasped through the humanities: historically, experientially, politically.
Race involves imposing some cultural patterns upon human differences. Troubles arise when social predilections lead us to mistake cultural facts for biological ones and vice versa. Races are not merely human divisions, they are politically salient human divisions. All classifications exist to serve a purpose; the purpose of a racial classification is to naturalize human differences—that is, to establish important categories and make their distinctions appear to be rooted in nature, rather than in history or politics.
Yet, dog breeding standards influence assumptions about hard-wired behavior characterizing and differentiating human groups. The jump from clustered physical variation to the assertion of superior and inferior, biologically-based behavioral variation at the group level is the crux of the matter.
From this mistaken perspective, the notion of race as a social construct is seen as absurd and so is down-playing the biological basis for race, because to do so is to be willfully stupid, ignorantly anti-science, or brainwashed by a politically correct denial of reality.
First, they establish that medical approaches to both human and dog disease share similarities; individual dogs and humans can be sensitive to different drugs and this is sometimes due to inherited genetic variants, which means that the risk varies between dog breeds and between human races.
Then, they ease into a discussion of an experiment where a scientist noted individual behavioral differences among several puppies of different breeds. First of all, as we have shown, the dog breed-human race analogy is not biologically sound—it assumes race as a natural biological category of humans, a priori.
Second and inextricably related, the analogy denies sociocultural context, both past and present. What is more, it includes unquestioned and largely unfounded assumptions about genetically-determined and predictable human behavior. Scientists are still discovering whether and how dog behaviors are breed-specific and, when they are, how heritable they are.
There is much known but also much more to learn about what else influences behavioral variation among dogs like weaning age, diet, and other conditions during development.
A recent meta-analysis of the heritability of dog behavior concluded that not only are breed standards poorly aligned with the actual behaviors of the breeds they aim to define, but they describe behaviors with little genetic component in the first place Hradecka et al. These meta studies emphasize that variable behavior within breeds is often overlooked.
They also highlight how difficult it is to operationalize behaviors like aggression and intelligence and how difficult it is to measure and compare intelligence in dogs; some dogs solve problems thanks to their relatively heightened senses of smell, while for others it is thanks to their higher energy that keeps them active long enough to solve the problem by chance Mehrkam and Wynne In the zeitgeist, scientific enthusiasm for genetics has encouraged genetic essentialism, which is the tendency to consider genetic outcomes to be immutable and determined, to prioritize the influence of genes on complex outcomes, to view groups with shared genetic heritage as homogeneous and discrete, and to view genetic outcomes as the most natural and even to be the most morally acceptable Dar-Nimrod and Heine Genetic essentialism, where genes are synonymous with essence, is fertile ground for beliefs that meaningful, distinctive individual behaviors have a predictive individual biological basis even in the absence of any identified genes.
Variation in human behavior has its roots in both complex genetic and non-genetic factors. Claims that such factors, or their interactions, map neatly onto geographically and socially constructed human groups and can be used to predict behavioral traits associated with such groups, or of an individual member of a group, are not scientifically supported.
Hierarchical ranking of human races is also inherently competitive, which is just one reason why outdated and overly simplistic conceptions of evolutionary biology have historically paired with racism, and still do.
Within this racist framework, hindsight paints the dominant group as the more genetically intelligent and naturally selected one, justifying its dominance with perceived biological superiority. In many cases, perpetual mutation and drift are enough to explain evolutionary divergence Hedges et al. The need for such a foundation or some intellectual justification for the enslavement of Africans and the oppression and exploitation of indigenous peoples during the period of European colonization and its subsequent racisms—without question motivated belief in human races [as real and important, biologically differentiated types of humans].
People, scientists and nonscientists alike, are susceptible to the same biased thinking and assumptions as they make sense of human biological variation and human social, economic, and political inequality and the intersections of those phenomena.
Over 30 years ago, biology educator, Vance described this problem and how educators were complicit. He argued that scientists and science educators are racist if they are not actively facing the racism that appeals to science. Science educator Brian Donovan is attempting to engage exactly as Vance suggests with junior high school biology students. Figure 1 from Donovan , but with our addition of the red box. He also found that they were less interested in socializing across racial lines and were more opposed to policies aimed at reducing racial inequalities in education.
But, if it does, it should also teach students that inequality can be sustained when people are led to believe that racial difference is genetic. The existence of the erroneous human race-dog breed analogy suggests that there may be unintended negative consequences of using artificial selection as a model for teaching natural selection.
Since artificial selection can produce relatively discrete between group variation and low heterozygosity in a short period of time, perhaps models of artificial selection as teaching tools are inappropriate for middle or high school biology education.
Perhaps the answer is not to take artificial selection out of curricula because dogs, cats and other familiar organisms make for engaging pedagogy , but to explicitly and rigorously juxtapose it against the rest of evolution. For example, hands-on activities that explore the different ways that evolutionary forces such as selection, gene flow, and drift e. Lee et al. This paper bridges academic literature and popular culture. Not an insignificant proportion of Americans refuse mainstream academic knowledge; our paper offers a way forward for those caught up in that culture regarding race.
The dog breed-human race analogy is destructive; if folks see how it does not stand up to biology, then maybe they will better understand the complexity and significance of race.
Several decades ago, well before most of the research we cited here was possible, Montagu covered familiar territory:. The Irish setter, for example, is always red-haired, but his red hair has no connection with his temperamental qualities.
The Irish setter has the same kind of temperament as the English setter, but the hair color of the English setter is white and black. The only difference between the white, the black, the white and black, and the red setters is in their coat color; there are no significant differences in their mental or temperamental qualities. No one ever asks whether there are mental and temperamental differences between white, black, or brown horses—such a question would seem rather silly.
When, however, it comes to man, the prejudice of anyone who has ever made the statement that skin color is associated with mental capacity is accepted as gospel. For such an assumption there is about as much justification as there would be for the assumption that there exist substantial differences between different color varieties of setters. We know this to be false concerning setters only because we have paid more unprejudiced attention to the mental qualities of dogs than we have to those of human beings.
Scholars and critics may assert that because science has a history of encouraging racialism, scientific racism, and racist appeals to science, then science should step aside in this endeavor. But we believe that racist appeals to science deserve scientific rebukes, at least as one kind of strategy among many. While we have attempted here to address one very specific belief about human variation, it is embedded in widespread, biased assumptions about dogs and within a dauntingly complex history of science and its sociocultural consequences.
Anthropologists, evolutionary biologists, geneticists, scientists, scholars, academics, teachers, writers, journalists, parents, and citizens must move the popular conception of human evolution and human variation past the days of Blumenbach and Darwin.
To do so means to question not just what we think we know about ourselves but what we think we know about everything around us too. Being so familiar and so widely adored, dogs have significant potential to untether racism from evolutionary biology, for good. Toward that end, we showed that the categories we impose on humans and dogs are different in important ways, and that the comparison lends no science to racism.
Equating the differences between two human beings to the idealized differences between a greyhound and a bulldog is the province of poetry or prejudice, not science. Nat Commun. Adhikari K, et al. American Association of Physical Biological Anthropologists. AAPA statement on race and racism.
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Mother Jones 27 October Harrington P. No mongrels need apply. NIH encourages institutions to diversify their student and faculty populations to enhance the participation of individuals from groups identified as nationally underrepresented in the biomedical, clinical, behavioral and social sciences.
These groups include: individuals from underrepresented racial and ethnic groups, individuals with disabilities, individuals from disadvantaged backgrounds and women at senior faculty levels in biomedical-relevant disciplines.
These standards are commonly used for federal data collection purposes, not only in the decennial census, but also in household surveys, on administrative forms e. The categories and definitions provide a common language to promote uniformity and comparability of data on race and ethnicity. Moreover, federal agencies have a continuing commitment to monitor the operation of its review and award processes to detect, and deal appropriately with, any instances of real or apparent inequities.
All analyses conducted on race and ethnicity report aggregate statistical findings and do not identify individuals.
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