
A newborn's eye colour can change over time, and it may take a few years for their eye colour to be set permanently. Melanocytes are responsible for the colour of a baby's eyes, and they respond to light. When a baby is born, their eyes may appear grey or blue due to the lack of pigment and because they have been in a dark womb. As babies are exposed to more light, their eye colour can change over time. The most dramatic eye colour changes will probably occur when a baby is between three and six months old. However, their eye colour may continue to change until they are three years old or even six years old.
Characteristics | Values |
---|---|
Time taken for newborn eyes to change colour | The most dramatic eye colour changes occur between 3 and 6 months old. The colour does not change much after 6 months of age. However, the eye colour can continue to change for several years. |
Eye colour at birth | Most babies are born with blue eyes. However, this is not always the case. Babies with darker skin are usually born with brown eyes. |
Factors influencing eye colour | Melanin, a protein that releases cells called melanocytes, determines the eye colour. Melanocytes respond to light, which is why a baby may have eyes that appear gray or blue at birth due to the lack of pigment and being in a dark womb. |
Permanent eye colour | Permanent eye colour is usually set by the time a baby is 6 years old. However, about 15% of people experience changes in eye colour throughout their lives due to their genetic makeup. |
What You'll Learn
Melanin and melanocytes determine eye colour
The colour of a newborn's eyes is determined by the amount of melanin in the front layers of the iris. Melanin is a pigment produced by melanocytes, which are special cells that also give a baby's skin its colour. The amount of melanin produced by melanocytes determines the colour of the iris, which can range from very pale blue to very dark brown.
Melanin production is influenced by genetics, with multiple genes determining the amount and quality of melanin present in the iris. The OCA2 gene, for example, is involved in the maturation of melanosomes, which are cellular structures that produce and store melanin. The amount of melanin produced by melanocytes can also be influenced by the amount of light exposure, as melanocytes respond to light.
At birth, a baby may have eyes that appear gray or blue due to the lack of pigment and because they have been in a dark womb. As a baby is exposed to more light, their eye colour can change over time, even up to several years. If the melanocytes secrete just a little more melanin, a baby may end up with blue eyes. A little more melanin, and their eye colour may be green or hazel. Brown eyes, which are the most common, are the result of very active melanocytes secreting lots of melanin. Brown eyes are likely to remain brown throughout life.
While the rate of colour change slows down after a baby is about 6 months old, the colour can still change after this time and sometimes the change can continue for several years before the eye colour becomes permanent.
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Blue eyes are the least pigmented
The colour of a newborn's eyes depends on the amount of melanin in the iris, which is the coloured part of the eye. Melanin is a pigment produced by cells that gives colour to the skin, eyes, and hair. Blue eyes have the least amount of melanin among all eye colours.
Blue eyes are the result of a genetic mutation that occurred between 6,000 and 10,000 years ago in Europe. This mutation affected the OCA2 gene, creating a “switch” that turned off the ability to produce brown eyes. All blue-eyed individuals are distant relatives of this ancient human and are linked to the same ancestor.
The iris of a blue-eyed person lacks melanin, so technically, their eyes are entirely colourless. The blue colour is caused by the absorption and reflection of different wavelengths of light. The lack of melanin causes fibres in the iris to absorb longer wavelengths of light (like red and yellow) and reflect shorter wavelengths (like blue), making the eyes appear blue.
At birth, a baby's eyes may only be temporarily blue. It can take up to six months for the gene responsible for producing melanin to activate. During this time, the baby's eyes may shift from blue to brown. If the gene doesn't activate or only partially activates, the eyes may remain blue.
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Brown eyes are the most common
The eye color of a newborn baby can take several years to settle, with the most dramatic changes occurring between three and six months old. However, the color can still change after this time, and by the age of three, the eye color is usually permanent.
Brown eyes are far more common in warmer climates, as the melanin helps to protect the eyes from sunlight. This is why brown eyes are more prevalent in countries in Africa and Asia, and among people of African and South Asian descent.
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Eye colour can change up until age 6
The colour of a newborn's eyes can change over time, and it can take months or even years for their eye colour to become permanent. Melanocytes, which are cells that secrete the pigment melanin, are responsible for eye colour. Melanin is produced by exposure to light, and the amount of melanin in the iris determines its colour.
While the most dramatic eye colour changes typically occur between the ages of three and six months, babies' eye colour can continue to change until they are one year old. You may even notice subtle changes until they are three years old. However, brown eyes, which are the most common eye colour, tend to remain brown throughout life.
Additionally, about 15% of people experience changes in their eye colour throughout their lives due to their genetic makeup. This is because eye colour is influenced by multiple genes and is not solely determined by the eye colours of the parents.
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Eye colour is influenced by genetics
The eye colour of a newborn baby is influenced by genetics. The colour of the iris, which is the muscular ring that surrounds the pupil, is determined by the amount and type of pigment called melanin stored in it. Melanin is a yellow-brown pigment that also determines skin tone. The colour of a newborn's eyes is usually related to their skin tone. White babies tend to be born with blue or grey eyes, while black, Hispanic, and Asian babies are commonly born with brown or black eyes.
Eye colour is a polygenic phenotypic trait, meaning that it is influenced by multiple genes. Scientists once believed that eye colour was determined by a single gene, but advances in genetic research have revealed that it is influenced by more than 50 genes. The main genes influencing eye colour are OCA2 and HERC2, which are located on human chromosome 15. However, as of 2010, up to 16 genes have been associated with eye colour inheritance.
The inheritance pattern of eye colour is complex and cannot be predicted with certainty. While brown eyes are generally dominant, and blue eyes are recessive, the presence of other genes can interact with OCA2 and HERC2 to influence eye colour. For example, green eyes are recessive to brown but dominant to blue. Although rarer than other colours, green eyes can result from the interaction of multiple allelic variants of OCA2 and other genes.
The amount of melanin in the iris is determined by the genes inherited from each parent. Each gene has two different versions, and the combination of these genes from both parents determines the eye colour of the baby. If a trait is recessive, like blue eyes, it usually only appears when the versions of the gene from both parents are the same.
It is important to note that eye colour can change over time. Most pigment is produced during the first six months of life, and permanent eye colour is typically established by the time a child is around one year old. However, in some cases, eye colour can continue to change until the child is three years old.
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Frequently asked questions
Newborns with lighter skin are usually born with blue, grey, or green eyes, which may change several times during the first year as melanin production changes, resulting in a darker eye colour. The most dramatic eye colour changes typically occur between three and six months old, but the eye colour may still change up until the child is six years old.
The final eye colour depends on the amount of melanin in the iris, which is influenced by the baby's parents' genes. However, it is not as simple as a blend of the parents' eye colours, and it is hard to make predictions about the shade.
Most babies are born with blue eyes, but some newborns with darker skin are born with brown eyes.