First published December 16, 2021.
Kalani and Jarani Dean are twin sisters born on April 23, 2016, in Quincy, Illinois, to a white mother, Whitney Meyer, and a Black father, Tomas Dean. From the first minutes of their lives the girls looked strikingly different: Kalani had fair skin and blue eyes, while Jarani had brown skin. Their parents shared the story with NBC's TODAY show in the hope that people would see past skin colour, and the photos of the two girls side by side travelled around the world.
How can twins look so different? The short answer is that they are fraternal twins, and skin colour is shaped by many genes that each child inherits in a different combination. Here is what happened, what the family said and what genetics tells us about it.
The moment the family noticed
Meyer and Dean knew they were expecting twins, but they did not expect the babies to look so unlike each other. Meyer told TODAY that Kalani's skin was so light at birth that she asked staff whether her daughter might have albinism. Dean recalled thinking at first that newborns are sometimes pale, until Jarani arrived a few minutes later with noticeably darker skin. He was especially surprised by Kalani's blue eyes. "In a million years, I never thought I'd have a girl with blue eyes," he said.
For Meyer the difference never affected how she saw her daughters. Speaking to TODAY, she summed it up in a single line: "They're the same girl, just different colors."
Fraternal twins are genetically ordinary siblings
Identical (monozygotic) twins come from one fertilised egg that splits in two, so they share almost all of their DNA. Fraternal (dizygotic) twins develop from two separate eggs fertilised by two separate sperm. Genetically they are no more alike than any two brothers or sisters born years apart: on average they share about half of their genes.
That is why fraternal twins can differ in height, hair colour, eye colour and, yes, skin tone. The only unusual thing about Kalani and Jarani is that two quite different outcomes happened to arrive on the same day. Similar "mixed twins" have been reported elsewhere; one well-known pair was born in London in 1993 to a white mother and a father of Caribbean heritage.
How skin colour is inherited
Skin colour is not controlled by a single switch. It depends mainly on the amount and type of melanin produced in the skin: eumelanin, a brown-black pigment, and pheomelanin, a lighter red-yellow pigment. Many genes influence that process. Well-studied examples include MC1R, which affects the balance between the two pigments, and SLC24A5, SLC45A2, TYR, OCA2 and KITLG, which each nudge pigmentation up or down. One systematic study identified 169 genes involved in skin colouring.
Each parent carries two copies of every one of these genes and passes one copy, chosen more or less at random, to each child. When parents have very different ancestries, the number of possible combinations is enormous. Most children land somewhere in the middle, but some inherit mostly lighter-skin variants and others mostly darker ones.
Dr. Bryce Mendelsohn, a medical geneticist at the University of California, San Francisco, explained this to TODAY with a coin analogy. If you flip a coin eight times you will occasionally get eight heads in a row; shuffle enough genes and unusual combinations become possible too. He also noted that what we can see is only a tiny part of human genetic variation: "A lot of times we only focus on the things our eyes can see."
How rare are twins like Kalani and Jarani?
Headlines about "black and white twins" often quote dramatic odds, such as one in a million. There is no reliable statistic behind such figures, and they are best treated with caution. What can be said is that fraternal twins are common, mixed-ancestry families are increasingly common, and visible differences between siblings in such families are expected. Twins who sit at opposite ends of the range are uncommon but not mysterious.
It is also worth correcting a frequent shorthand. Many reports described the girls as "twins of different races". They are not. They share the same parents and the same mixed ancestry. As the US National Human Genome Research Institute explains, race is a social classification rather than a set of distinct biological categories, and skin tone is a poor guide to a person's ancestry or genetic makeup.
The family's message about acceptance
Dean said he hoped people would take one thing from the photographs: that colour is not what matters, and that love is. Both parents described the twins' arrival as a blessing and said they wanted their daughters to grow up knowing they are beautiful whatever their skin tone.
The story resonated because it turns an abstract idea into something easy to see. Two girls with the same parents, the same birthday and the same home look different to a stranger. Anyone who would treat them differently because of that is reacting to a surface feature, not to who the children are.
Talking with children about skin colour
Families like the Deans often get questions from curious kids. A few approaches that many parents and educators find helpful:
- Answer honestly and simply. Explain that skin gets its colour from a pigment called melanin and that people inherit different amounts from their families.
- Point out variety within families. Siblings, cousins and even twins can look different, which shows that appearance does not divide people into fixed groups.
- Focus on the person. As the twins grow, their interests, talents and personalities say far more about them than the feature that made them famous as babies.
Kalani and Jarani were five when this story was first shared here and are older now. Their parents' wish was modest and universal: that their daughters, and children everywhere, would be judged by character rather than complexion.
Sources: TODAY: twins born to Whitney Meyer and Tomas Dean; NHGRI: Race; Wikipedia: Twin; Wikipedia: Human skin color.
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