Can 2 brown eyes make blue eyes?
Can two brown eyes make a blue eye?
Yes, it’s possible for two parents with brown eyes to have a child with blue eyes. This is because both parents carry a recessive gene for blue eyes that can be passed down to their children.
Two brown-eyed parents (if both are heterozygous) can have a blue-eyed baby. If both the parents have brown eyes, then there is generally a 25% chance for their child to have blue eyes. Because both the brown-eyed parents have a recessive blue-eye gene and can pass it to the next generation.
However, if only one parent has a recessive blue-eye gene and the other has two dominant brown genes, the chance of a child having blue eyes is less than 1%.
Eye color is polygenic, meaning that several other genes also affect it. Geneticists represent the different versions of the eye color gene as B for brown and b for blue.
- Which parent determines eye color?
- How does a child get blue eyes?
- Can my kid have blue eyes if I don’t?
- Can two parents with brown eyes have a child with blue eyes?
Ask a follow up…
Eye color, like the many physical traits that we possess stem from our internal genetic infrastructure (genotype) inherited from both our parents. Humans traditionally have 46 chromosomes, all of which contain genes that express our physical outlook (phenotype).
Before reading more about How can two brown eyed parents make blue eyes? I suggest you go through below post to understand more about eye color genetics.
Genetics of Eye Colour: What does your eye colour says?
How is eye color genetically inherited?
The interactions between various genes have been found to determine color pigmentation in humans. However, specifically, HERC2 and OCA2 genes located on chromosome 15 are associated with eye color. Different studies have shown that specific Single Nucleotide Polymorphism (SNP) position on the OCA2 gene determines the presence of brown or blue eyes.
The research was done to find out the genes that are associated with human pigmentation showed that HERC2 SNP rs12913832 was statistically significant when tested for the association with eye color. Within this SNP two alternative forms of a gene (allele) C and T DNA bases determines the color of the eye.
Since all chromosomes come in pairs, possible variations of this gene would be CC, TT (homozygous), and CT (heterozygous) with one allele being inherited from each parent.
Statistical results from a research done by Branicki et. al. (2009) showed the CC gene expressed 88.9% of blue-eyed subjects, CT and TT gene both expressing brown/black-eyed subjects with 84.4% and 15.6% respectively.
Eye color
Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the iris and the frequency-dependent scattering of light by the turbid medium in the stroma of the iris.
In humans, the color of the iris ranges from light brown to black, depending on the concentration of melanin in the iris pigment epithelium located at the back of the iris, the melanin content within the iris stroma located at the front of the iris, and the cellular density of the stroma. Blue, green, and hazel eyes appear due to the Tyndall scattering of light in the stroma, a phenomenon similar to Rayleigh scattering that causes the blue sky. The human iris and vitreous humour lack blue or green pigments, resulting in structural color that is dependent on lighting conditions, particularly for lighter-colored eyes.
In contrast, the brightly colored eyes of many bird species are due to the presence of other pigments, such as pteridines, purines, and carotenoids. Eye color in humans and other animals exhibits numerous phenotypic variations.
The genetics and inheritance of human eye color are complex. As of 2010, research has identified up to 16 genes that contribute to the inheritance of eye color. Among these genes are OCA2 and HERC2. It was previously believed that blue eyes were solely a recessive trait, but this has been proven incorrect. The genetics of eye color are so intricate that any combination of eye colors can occur between parents and their children. However, the OCA2 gene polymorphism, located near the proximal 5′ regulatory region, is responsible for the majority of human eye color variation.
Can two brown eyes parents make a blue-eyed child?
As research has shown that genes are associated with eye color, we can now predict if it is possible that two brown-eyed parents to have a blue-eyed child. This can be easily determined by using a Punnett’s square, where possibilities of the parent genotypes are used to check the probability of what genotype a child would inherit.
Since both parents are brown-eyed their genotypes would either be CT and CT, TT and TT, or CT and TT:
- Conclusion: If both brown-eyed parents are both heterozygous CT there would be a 25% chance that their child would inherit the CC gene and have blue eyes.
- Conclusion: If both brown-eyed parents are both TT none of their children would have blue-eyes.
- Conclusion: If both brown-eyed parents are either CT or TT none of their children would have blue-eyes.
From the research by Branicki et. al. (2009), we have done a Punnett’s square test and shown that both parents have to be heterozygous CT in order for their child to have 25% probability of inheriting blue eyes.
This was also discussed in an article by www.science daily.com where they highlighted that it is possible for brown-eyed parents to have a blue-eyed child.
So don’t go running out to do paternity tests just yet when you see your child with a different eye color. He/she might just have been the 25% of the gene pool having blue-eyes even though you and your spouse have brown-eyes.
References
- Branicki, W., Brudnik, U. and Wojas-Pelc, A. (2009), Interactions Between HERC2, OCA2 and MC1R May Influence Human Pigmentation Phenotype. Annals of Human Genetics, 73: 160–170.
- Springer. “Blue Eyes — A Clue To Paternity.” ScienceDaily. ScienceDaily, 23 October 2006. https://www.sciencedaily.com/releases/2006/10/061023193617.htm
- Sturm, R. A. and Larsson, M. (2009), Genetics of human iris colour and patterns. Pigment Cell & Melanoma Research, 22: 544–562.
FAQ
Can two brown eyes make a blue?
Yes, it’s possible for two parents with brown eyes to have a child with blue eyes. This is because both parents carry a recessive gene for blue eyes that can be passed down to their children.
How is eye color inherited?
Eye color is inherited through genes passed down from both parents. Brown eyes are dominant and blue eyes are recessive. For a child to have blue eyes, they need to inherit two copies of the recessive blue eye gene, one from each parent. If a child inherits one or two copies of the dominant brown eye gene, they will have brown eyes.
What if one parent has blue eyes and one has brown, can they have a blue-eyed child?
Yes. If one parent has blue eyes and the other has brown eyes, they can have a blue-eyed child. The blue-eyed parent contributes the recessive blue eye gene and the brown-eyed parent contributes either the brown dominant gene or the blue recessive gene. There is a 50% chance the child inherits two blue eye genes and has blue eyes.
How likely is it for two brown-eyed parents to have a blue-eyed child?
It is extremely unlikely, essentially impossible, for two brown-eyed parents to have a blue-eyed child. For a child to have blue eyes, they need to inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents can only pass on the dominant brown eye gene, not the recessive blue gene, so a blue-eyed child is not genetically possible.
Can a blue-eyed child be born to parents who both have brown eyes?
No, it is genetically impossible for two brown-eyed parents to have a blue-eyed child. Brown eye color is dominant over blue eyes. For a child to have blue eyes, they must inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents can only pass on the dominant brown gene, not the recessive blue gene.
What are the chances of having a blue-eyed child if both parents have brown eyes?
There is zero chance of two brown-eyed parents having a blue-eyed child. Since brown eyes are dominant over blue eyes, two brown-eyed parents can only pass on the gene for brown eyes. They do not carry the recessive gene for blue eyes that would be needed for their child to have blue eyes.
Is it possible for two parents with brown eyes to produce an offspring with blue eyes?
No, it is genetically impossible for two brown-eyed parents to produce an offspring with blue eyes. For a child to have blue eyes, they must inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents can only pass on the dominant brown eye gene, not the recessive blue gene, making a blue-eyed child impossible.
Can brown eyes turn blue later in life?
No, it is not possible for brown eyes to turn blue later in life. Eye color is determined by the genes inherited from your parents and does not change over time. The only colors brown eyes could potentially shift toward are hazel or green, but blue is not genetically possible if you were born with brown eyes.
If my grandparents had blue eyes, can two brown-eyed parents still have a blue-eyed baby?
No, if both parents have brown eyes, they cannot have a blue-eyed baby even if the grandparents had blue eyes. For a baby to have blue eyes, they must inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents only carry the dominant brown eye gene to pass on, not the recessive blue eye gene.
How rare is it for two brown-eyed parents to have a blue-eyed child?
It is essentially impossible, so the odds are zero. For a child to have blue eyes, they must inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents can only pass on the dominant brown eye gene, not the recessive blue gene, making a blue-eyed child genetically impossible.
If I have brown eyes and my partner has brown eyes, could we have a baby with blue eyes?
No, two brown-eyed parents cannot have a blue-eyed baby. Since brown eyes are dominant over blue eyes, when both parents have brown eyes they will pass on the gene for brown eyes to their children. A blue-eyed child would only be possible if one parent had blue eyes themselves and passed on the recessive gene.
Can hidden genes cause two brown-eyed parents to have a blue-eyed child?
No. There are no 'hidden genes' that could cause two brown-eyed parents to have a blue-eyed child. For a child to have blue eyes, they must inherit two copies of the recessive blue eye gene, one from each parent. Two brown-eyed parents simply do not carry that recessive gene to pass on to their offspring.
What are the genotypes of blue and brown eyes?
People with blue eyes have a genotype of bb, meaning they inherited two copies of the recessive blue eye gene, one from each parent. People with brown eyes have a genotype of either BB or Bb, because the brown eye gene (B) is dominant. To have blue eyes with genotype bb, you need to inherit a b gene from each parent.
Can someone with brown eyes carry the blue-eyed gene?
Yes, it is possible for someone with brown eyes to carry the recessive gene for blue eyes. This would give them a genotype of Bb. However, the dominant brown gene (B) masks the recessive blue gene (b), so their eyes remain brown. They can pass on the recessive b gene to their children though.
If I have brown eyes but my child has blue eyes, what does that mean?
It would mean your genotype is Bb, meaning you carry one dominant brown eye gene (B) and one recessive blue eye gene (b). Your child's other parent would also need to have contributed gene b for your child to end up bb and have blue eyes. So while your brown eyes mask your recessive blue gene, you still passed that gene on to your blue-eyed child.
Why do some babies' eye colors change from blue to brown?
Babies can be born with blue eyes that later darken into brown eyes. This occurs if the baby has genotype Bb or BB. The initially lighter eye color becomes darker as more melanin pigment develops in the iris over the first couple years of life, turning blue eyes brown.
Can brown and green eyes make blue?
No. For a child to have blue eyes, they need to inherit two copies of the recessive blue eye gene (bb genotype), one from each parent. If one parent has brown eyes and the other has green eyes, their genes for brown/green eyes are still dominant over blue eyes. They would each need to carry and pass on the recessive b gene for their child to end up bb blue eyes.
Why do siblings sometimes have different eye colors?
Siblings can have different eye colors because each child inherits a different combination of the gene variants (called alleles) for eye color that get passed down from their parents. Parents each have two alleles for eye color, and each child randomly inherits one allele from mom and one allele from dad. This creates variation among siblings.
My husband and I both have dark brown eyes. Can we have a baby with green eyes?
Yes, it's possible for two brown-eyed parents to have a green-eyed baby. Brown eyes are dominant over green, but you could both be carriers of the recessive gene variant for green eyes. There's a 25% chance that a baby inherits recessive green alleles from both parents and ends up with green eyes.
What are the chances two brown-eyed parents can have a hazel-eyed child?
It's possible for two brown-eyed parents to have a hazel-eyed child. Hazel eyes are a mix of brown and green. If both brown-eyed parents carry recessive alleles for green eyes, their child could inherit one brown allele and one green allele from each parent, resulting in hazel eyes. The chances depend on whether the brown-eyed parents carry green alleles, but there's a possibility.
How can a brown-eyed child be born to blue-eyed parents?
A brown-eyed child cannot be born to two blue-eyed parents. Since blue eyes are a recessive trait, two blue-eyed parents can only pass on genes for blue eyes, not brown eyes, to their offspring. For a child to have brown eyes, at least one parent must have brown eyes themselves and pass on the dominant brown eye gene.
If my grandparents on both sides had blue eyes, why do I have brown?
Even if your grandparents on both sides have blue eyes, you can still have brown eyes if both of your parents have brown eyes. Eye color inheritance ultimately comes directly from your parents' genes, not your grandparents. Your parents both passed on a copy of the dominant brown eye gene, making your eyes brown rather than blue.
Why do some babies with blue-eyed parents end up with brown eyes?
This can happen if the blue-eyed parents both carry the brown eye gene as well as the blue eye gene. Blue eyes are recessive so even if the parents have blue eyes, they may genetically have the genotype Bb, still carrying the dominant brown eye gene to potentially pass on to their babies which results in brown eyes.
Is it possible for Asians with brown eyes to have a blue-eyed baby?
It's extremely rare but theoretically possible for two brown-eyed Asian parents to have a blue-eyed baby if both parents carry the recessive gene mutation for blue eyes. The odds depend on whether hidden recessive blue eye genes exist in the family ancestry but the chances are very slim.
Why do some children end up with lighter eye colors than either parent?
This can happen if both parents carry a mix of genes for different eye colors. For example, two brown-eyed parents could each carry recessive genes for green or blue eyes. If their child happens to inherit two copies of the lighter recessive genes (one from each parent), they may end up with green or blue eyes.
Can someone with blue eyes have a brown-eyed child?
Yes. If someone with blue eyes has a genotype of Bb rather than bb, they can have a brown-eyed child. The B represents the dominant brown gene, while the b represents the recessive blue gene. Although the blue-eyed parent's brown gene B is masked by the blue gene b in their own eyes, they can still pass the B gene on to their child resulting in brown eyes.
What is the rarest eye color for humans?
The rarest natural eye color in humans is amber eyes, which have a strong yellowish/golden appearance rather than just being light brown. Only about 5% of the global population has amber eyes. Green is also a relatively uncommon eye color at around 2% of people worldwide.
Why do people from the same ancestry sometimes have different eye colors?
People from the same ancestral background can have varying eye colors because of the different combinations of eye color genes that get passed down through the generations. There is natural genetic variation so that recessive genes can stay hidden for generations before resurfacing again. This natural genetic shuffling leads to differences even within families.
Can someone with green eyes have a blue-eyed parent and a brown-eyed parent?
Yes, it is possible for someone with green eyes to have a blue-eyed parent and brown-eyed parent. This would happen if the blue-eyed parent was a carrier of brown eye genes and the brown-eyed parent was a carrier of blue eye genes. By inheriting one green allele from each parent, the child ends up with green eyes.
How rare are blue eyes globally?
Only around 8-10% of the global population has blue eyes. In contrast, brown eyes are the most common worldwide, with an estimated 79% of people having them. So while eye color diversity and recessive genes still exist and reshuffle, blue eyes are relatively uncommon on the global scale.
What determines if parents with dark brown eyes can have a lighter-eyed child?
If both parents have dark brown eyes but carry recessive genes for lighter colors like green or blue, there is a possibility they could have a lighter-eyed child. Each child randomly inherits one eye color gene from each parent. So a lighter eye color could surface if a child happens to inherit two copies of recessive lighter color alleles.
Can someone with sectoral heterochromia (two different eye colors) have a baby with blue eyes?
Yes, it's possible for someone with sectoral heterochromia to have a blue-eyed baby. As long as one of their iris colors is blue and that blue eye color gene gets passed down, their child could inherit two copies of that recessive blue eye gene and also end up with blue eyes.
Why are blue and green eyes not common in African and Asian ancestry?
The genes associated with lighter eye colors like blue and green never underwent positive natural selection in populations originating from Africa and Asia. Therefore, alleles for lighter eyes either didn't exist or stayed extremely rare in these ancestral genetic pools. Populations centered more in European origins saw positive selection pressure for lighter eye colors.
Can someone with complete heterochromia (two totally different eye colors like brown and blue) pass on their two iris colors?
No, a person with complete heterochromia cannot directly pass on their two different iris colors. Their offspring would inherit whichever eye color corresponds with the eye color genes they receive, one from each parent - either the gene coding for brown OR blue eyes, not one gene from each.
How rare are light eyes among African descendants globally?
Extremely rare. Over 99% of people with African ancestry across the globe have brown eyes. Light eyes including blue, green and hazel continue to be exceptionally uncommon among most populations that trace back lineage to Africa due to lack of genetic selection for those traits over history.
Why do some mixed children seem to have an eye color totally different from either parent?
This can happen because mixed children often have greater genetic variation compared to parents from a more uniform background. Recessive genes on either side have more opportunities to combine and express new traits including unexpected eye colors neither parents exhibits but both unknowingly carried in their mixed DNA.
Would it be likely for an Asian person with brown eyes to carry recessive blue eyed genes?
It is highly unlikely but remotely possible. Blue and green eye genetic mutations are extraordinarily rare among indigenous Asian populations. But dormant recessive versions could have mixed in during migrations over history at infinitesimal rates. Unless there are records of light eyes within Family history though, presence of that recessive allele would be very doubtful.
Why do some children from the same parents develop lighter eye colors over time while their siblings’ stay dark brown?
This can happen if some children inherit a mix of eye color genes from parents while their siblings inherit predominantly darker color genes. For example, if both parents are actually Bb brown + blue gene carriers, some kids could randomly inherit two brown genes while others inherit a blue gene that leads to green/hazel eyes showing up gradually.
Would it be genetically possible for a biracial African and European couple to have a blue eyed child?
Yes it would be possible since the European parent could carry recessive genes for blue eyes and the African parent could carry brown eye genes. Their child would have a 25% chance of inheriting blue genes from both parents and expressing rare blue eye color despite partial African ancestry where that is an uncommon trait historically.
Do people from certain minority ethnic groups never have light colored eyes?
No, while exceptionally rare, light eye colors can still occasionally occur among any ethnic population. Recessive gene reshuffling and distant mixed ancestry over generations allows unexpected traits to emerge. However the odds of light eyes appearing spontaneously in groups where that trait has very minimal documented heritage would be extremely low without recent mixed DNA integration.
What are some myths about eye color genetics?
Some common myths are that eye color is determined by a single gene, blue-eyed parents can never have brown-eyed children, eye color always breeds true based on grandparents’ or other relatives’ eye colors, and eye color can change later in life due to factors like diet, sunlight exposure, etc. In reality, multiple genes influence eye color, inheritance involves randomness, and diet/sun do not impact genetically-encoded iris pigment.
Can children’s eye colors continue getting darker generation after generation even when parents’ don’t?
Yes, genetically this is possible through an inheritance pattern called incomplete dominance. If both parents carry genes for lighter and darker eyes, children can end up with an intermediate eye shade that’s darker than parents’. Over generations, this blending of genes can lead to continuously darker eye colors in later generations.
Is it more common for lighter or darker eye children to be born to parents who don’t share their color?
It is more common for children to be born with darker eyes, like brown eyes, compared to lighter eyes when their parents have different eye shades. This is because genes coding for darker pigmentation tend to be more dominant. Without light eye recessive genes contributed from both parents, brown dominance leads to darker eye colors propagating through generations.
What determines if children will have lighter or darker eyes compared to their parents?
Whether children have lighter or darker eyes relative to their parents depends on the assortment of eye color genes each parent contributes. If both parents carry hidden recessive genes for lighter eyes, children have chances to end up with lighter eyes. Conversely, if both carry dark pigment genes, darker eyes can prevail in subsequent generations.
Why do some children end up with hazel eyes when neither of their parents have hazel eyes?
Hazel eyes are a mosaic of light and dark color genes. This blend can happen in children even when it’s not expressed in parents if parents carry hidden recessive genes for lighter colors like green or blue and dominant genes for brown. By inheriting one type from each parent, combinations emerge in children like hazel that parents don’t exhibit.
Can dormant genes reactivate unusual eye colors generations later even with no recent genetic mixing?
Yes, scientifically this is very possible through genetic recombination - recessive genes can be passed silently without expressing traits for many generations before finding just the right gene pairings from both parental sides to become active again. With no new mixing, surprise genetic activation of atypical dormant genes can still transpire.
Do colors ever skip generations?
Yes. For example, light eye colors can skip generations if grandparents have blue eyes but parents have brown. This means the parents still carry recessive genes for blue eyes, which can then get expressed again a generation later if the right gene combinations arise between parents’ egg and sperm cells, leading to a blue-eyed grandchild. Genes can remain dormant for generations before reemerging.
Can children have eye colors that combine the shades of their parent’s eyes?
Yes, children can end up with an eye color that seems to blend the attributes of their parents’ eyes. This happens due to inherent randomness in inheritance. Each parent passes down one eye color allele. If parents have varying shades, fusion of distinct genes from both sides can lead to an eye color in kids that’s a mix of parental hues.
Why does eye color vary drastically even among biological siblings?
Differences in eye color among siblings occur because each child inherits a random assortment of the available eye color genes carried by both parents. Through shuffling and recombining of parents’ eye color alleles - copying one variant from mom and another from dad - genetic variation emerges among different birth orders leading to striking eye shade differences.
What gene variants determine if parents with dark eyes can have children with blue eyes?
Parents with darker eye colors conceivably having blue-eyed children comes down to the OCA2 and HERC2 gene variants contributed by each parent. If both parents carry recessive OCA allele versions paired with HERC2 blue-eye-associated genes, offspring can end up with two copies of recessive OCA + HERC2 combos - yielding rare blue eyes.
How does someone distinguish between black eyes versus really dark brown eyes?
True black eyes with no iris pigment variation + pupil differentiation are exceptionally uncommon in most populations. Instead, extremely dark brown eyes are often perceived as black. But dark brown irises still contain hints of lighter flecks. So lack of any detectable iris color change under light reflects very deep brown rather than absolute black eyes.