Can a child have a different skin color than his parents? Science knows such cases

– There is a known case of a family where the mother is a blue-eyed blonde with light skin, and the father is a human with dark skin and hair. Of their three children, one is pale, the other is dark, and the third is mulatto. But from the point of view of genetics, this is not surprising – explains Prof. dr hab. n. med. Ewa Ziętkiewicz, geneticist from the Institute of Human Genetics of the Polish Academy of Sciences.

In the photo: Duchess Meghan, Prince Harry and their son Archie

One of the threads that appeared in a high-profile interview that Duchess Meghan and Prince Harry gave a few weeks ago on Oprah Winfer’s show was the color of their son’s skin
As the princely couple said, even before the boy was born, members of the royal family were excited by the question, “how dark can Archie’s skin be”
The famous interview made many people interested in genetics and the principles of inheriting skin color and other features
– Can a child have darker skin than his parents? Maybe it happens quite often – explains prof. Ewa Ziętkiewicz. – However, this is only possible under one condition
Some traits are inherited monogenic in accordance with Mendel’s laws that we all learn about in school. However, in the case of most features related to human appearance, inheritance is much more complicated and depends on many genes – explains Prof. Ziętkiewicz
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The interview that Prince Harry and his wife Meghan gave to Oprah Winfrey aroused a lot of controversy, also because of the racist comments Meghan accuses of members of the royal family. Considerations about the color of the skin of the son of the princely couple provoked enormous emotions. They both agree that even before the baby was born, there were discussions in the royal family about “how dark Archie’s skin could be.” Let’s put politics and customs aside. How would a geneticist answer this question?

Let’s start with what is known about the origins of both parents. Harry comes from a fair-skinned family, which seems to be quite well documented, as we know his parents, grandparents and even earlier generations. Meghan, in turn, is a mulatto girl – her mother is dark-skinned and her father is white. With this knowledge, I would assume that the child should not be darker than the mother. This is, of course, a speculative answer, and in order to explain what it results from, I would like to tell you more about inheritance of skin color.

So how is skin color inherited? Can a child have darker skin than the mother and ancestors?

Generally yes, but probably not in the case of the couple we are talking about. To start with, skin color inheritance is a typical polygenic inheritance.

What does it mean?

Certain traits, including many genetic diseases, are inherited monogenic, in a Mendelian fashion that we all learn about in school. However, in the case of most features related to human appearance, such as the color of the skin, eyes, height – inheritance is much more complicated and depends on many genes.

To understand why it’s so complex, you need to start with a biological basis. The observed skin color results from the presence of pigment in the skin cells – melanin. However, it is not only a question of the synthesis of this compound in the cell, but also of its type, quantity, transport and distribution in cells – all pieces of this puzzle are the result of the interaction of many proteins that are products of many different genes. In addition, the efficiency of each step depends on still other genes that regulate the action of the major ones. This is extremely complex, and all the models we can discuss and the predictions we can make are a simplification and approximation of the actual biological processes that produce skin color.

More than 120 genes are involved in the process that produces skin color, but about 20 genes that directly affect skin color variation in a population can be mentioned. “Bright”. The color of the skin will be the result of the interaction of the variants of all these genes received from the parents. The effect of genes here is additive, it results from the summation of the effects of individual genes – the more variants responsible for dark skin from different genes a child receives, the stronger the effect (darker skin) will be.

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Coming back to the question, can a child have darker skin than his parents. Maybe – and it happens quite often, but always on the condition that both parents had both dark skin and light skin variant genes. For a single gene it would be simple – a child who gets the dark variant from the mother and the father will be dark if he gets the light variant from both parents – clear, and if he gets the dark one from the other and the light one from the other – it will be intermediate. But the pigmentation genes are many and they work together. If we combine the described effect with the action of other genes, we get an additive effect – the total number of versions responsible for dark skin, coming from different genes, must exceed a certain level for this to become visible in the form of a specific skin color.

Quite a complicated puzzle.

It is not the end! Some genes are more strongly expressed while others are less active. For example, if the variants of the most potent genes are the same in both parents (for example, two bright and two bright), and at the same time in different genes, the parents will have different variants, the influence of these weaker genes will be more clearly revealed in the offspring.

Let’s go back to Harry and Meghan for a moment. Knowing that his family has been people with white skin for at least several generations, we can conclude that the chances that the couple’s child will have darker skin than the mother is small. Although in general theory it is possible.

Yes. If you take a random pair of people with light skin, then without knowing whether in the history of a woman or a man in any generation there was no ancestor with dark skin, you cannot predict what the distribution of light and dark variants is, let alone, what will be their child. On the other hand, if two people of mixed origins, such as Meghan, are expected to have offspring, it can be expected that they will have a chance of a child with lighter, darker or intermediate skin.

So is it possible for parents with white skin to have a child whose skin is not XNUMX% white?

Yes, although it will not be a child with skin commonly known as black. If a child is born with coffee or light brown skin, a mulatto, it will prove that somewhere among the parents’ ancestors there were people with dark versions of genes.

For how many generations can the genes responsible for dark skin remain hidden and suddenly make themselves known?

I wouldn’t want to risk an answer. This question reminds me of the United States of America when slavery was abolished. White society wanted – after all – to somehow distinguish itself from the dark-skinned. So the principle of “one drop of blood” was adopted – sleepless from a genetic point of view. Any ancestor with dark skin, many generations ago, made the child “black”. Apart from the political incorrectness of such assumptions, it could be that due to a kind of lottery related to the passing on of parental genes in subsequent generations, there were no longer any “dark” gene variants in a given person. In some states, to qualify as “white,” you had to be sure that his or her lineage had not been black for a minimum of five generations.

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I understand that this theory is politically incorrect, but from a scientific point of view it is probably not entirely impossible.

If there was a single black human in the pedigree, then after five generations, due to gene sorting, their dark variants might have disappeared altogether; but some combinations of them might as well have survived. This does not mean, however, that dark skin has survived, because as you know, inheritance is polygenic 

So little Archie could have darker skin if there was a dark-skinned person somewhere among Harry’s ancestors, and not too far away in terms of the number of generations?

That’s right. Therefore, as I said at the beginning, I assume that the chance of having a darker baby is slim.

Many people who are not very familiar with the rules of inheritance think in a simple way: the longer the genes of dark-skinned people connect with light-skinned people, the lighter their skin is.

The more light element admixed, the lighter the skin is, that’s true. I have only one comment – the commonly accepted opinion is that the dominant color is dark or, in other words, that the child from the relationship between a white person and a dark-skinned person will be dark. Please note that this approach is Eurocentric – we identify any person who has a slightly darker color, slightly brown skin, as a mulatto, whether they have 1/8, 1/16 or 1/64 admixture with dark gene variants. In Africa, the situation is exactly the opposite – there we have a whole range of blacks, and for an ebony-dark African, a person who is the color of chocolate can be considered “white”. This influences the perception of which genes – light or dark – are dominant.

Indeed, it is very easy to break into racist tones here …

The concept of race has long gone out of fashion. When it comes to skin color, it’s hard to talk about dark and light skin, because when you look at the world’s population, it’s one big color continuum. The skin color in the population is broken down according to the bell curve – the most mid-tones are, and the extremely light or extremely dark ones at both ends of the distribution are much smaller. Of course, if you take from both ends of this distribution, you will see a marked difference, but you can arrange people so that you don’t actually see any boundaries between the colors.

Science knows of parents who had children with a completely different skin color than themselves, and yet everything took place in accordance with the rules of inheritance?

There are known cases in the public opinion when parents perceived as white had a child whose skin was not entirely white. On the internet you can find pictures of the family where the mother is blue-eyed blonde with light skin and the father is dark. Of their three children, one is pale, the other is dark, and the third is mulatto. But from a genetics point of view, this is not surprising – for such parents, just such a distribution can be expected. However, even in the example given, as in the story of Harry and Meghan, the child with the darkest skin was not darker than his father, but similar to him.

Such stories are reported in the media as humorous and usually questioning a woman’s faithfulness.

People look at two white people with a darker child and say that this is not possible. However, if this relationship did not involve infidelity, there is only one possibility: somewhere in their lineage there were people with darker genes.

Meghan and Harry are expecting another baby. What could the color of his skin be?

Probably something between mother’s and father’s skin color as well. It will not be skin lighter than Harry’s or darker than Meghan’s. Everything in between is possible …

By the way, people are fascinated by skin color, and meanwhile, in a mixed marriage, you can expect children resembling one of the parents not only by skin color; I mean, for example, the color of the eyes or hair.

In addition to skin color, genes responsible for many other aspects of appearance – eye color, hair color – are also important in the process of inheritance. It is not that people with dark skin automatically have dark hair. There is a tribe among Australians that have dark skin and light hair. These are not albinos – just skin color and hair color genes are partly shared and partly not. Added to this is the eye color, which is usually typical – dark for dark-skinned people, although there can also be surprises here, depending on how the gene variants are arranged.

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Since you mentioned the color of your hair and eyes – what are the rules of inheritance in this regard?

The rules are very similar to skin color, except that slightly different sets of genes are involved. Most genes for skin and eye pigmentation are common, while some genes for eye color are different from skin color and vice versa. Consequently, while dark eye color is typical for dark-skinned people, there can be surprises depending on how the variants of the genes specific to skin and iris pigmentation break down. But the general principles are similar – this is polygenic inheritance, it is also interaction and multi-level regulation of many genes.

It is the same with hair – there we also have a whole spectrum of possible shades. Interestingly, it is not always the case that people with dark skin automatically have dark hair. Among Australians there is a tribe that has dark skin and light hair; They are not albinos – it is just that the genes responsible for skin color and hair color are partly shared and partly not.

In the case of hair, we can consider not only the color but also the structure of the hair: people can have straight hair like Asians, slightly wavy like Europeans, or woolly like Africans. The genes responsible for the structure and color of hair are completely different pools of genes, but the nature of inheritance is similar, polygenic.

What about blood groups, height, character traits, susceptibility to disease?

When it comes to blood groups – inheritance is more defined, we have fewer genes here. They are responsible for groups A, B, AB and 0, but also for different subgroups (e.g. Rh + and -) that can influence different health characteristics and so on.

Growth, on the other hand, is even more complicated than skin color – I do not even undertake to explain how many genes are responsible for it and how they interact. Complicating matters further is that growth also depends on the environment, for example the diet and way of life. A person who has the same genetic makeup may be taller or lower. These are the so-called examples of complex inheritance, where both the gene and the way we live are responsible for appearance. Character traits, intelligence are also features that depend on many genes and their interaction, and on the influence of the environment. As for the susceptibility to the so-called civilization diseases, depending on the gene variants we have, we have greater or lesser susceptibility to some of them (e.g. diabetes or hypertension), but here a lot also depends on the lifestyle, nutrition or air quality.

Blood groups – characteristics, inheritance, serological conflict [EXPLAIN]

One more important aspect that we haven’t talked about – which is how exactly did the different skin colors arise in human evolution?

Modern man was created about 150 thousand. years ago in Africa. The first people had dark pigmentation that created a natural filter to protect the skin from UV radiation. Gene variants associated with light skin and eye color developed after leaving Africa, around 30. years ago. In the northern, poorly sunny areas, light skin made it possible to synthesize vitamin D more efficiently and avoid diseases related to its deficiency. Gene variants associated with light pigmentation gave better survival and offspring chances and therefore spread throughout Europe. In summary, the skin color seen in humans today is not the result of a single mutation; Behind each shade of color lies a long history of the species’ evolution.

To sum up – inheritance is not a simple topic in which everyone can express themselves easily. It requires more knowledge.

Definitely yes. Even among scientists, it is a common belief that we don’t know everything about genes yet. We still do not have the full picture on many issues, especially those relating to the regulation of gene function or their interaction with the environment. And we certainly cannot reasonably predict appearance without knowing what gene variants are present in the parents. However, thanks to the development of science and research technology, knowledge about the inheritance of these complex characteristics is constantly expanding.

These are very interesting and very complex stories – a bit too long for such an interview. But I encourage you to read about the principles of genetics. This is a really fascinating field of science.

Can a child have a different skin color than his parents? Science knows such cases

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