When a light skinned person and a dark skinned person have a child, that child is likely to have a mix of those skin tones, resulting in a caramel hue. However, when someone with blond hair and someone with black hair have a child, the child would either have blond or black hair rather than a mix of the two producing brown.
And where do eye colour genes fall in here?
In: Biology
Genetics are half from one parent and half from the other. Some genes are stronger than others which is why they show up physically.
Even if a gene is present it might not physically show until several generations later. These are sneaky and usually show up when they meet another gene just like them (in this case two wrongs do make a right).
Usually darker pigments in skin will dilute lighter ones. Brown eyes are dominant to most other colors.
Genes themselves don’t mix. Other than the genes on sex chromosomes, chromosomes come in pairs, where one comes from each parent, and when you have children, they get half of your and half from the other parent.
For a few specific traits, there is a single gene or very small number that cause that trait to be expressed. For a lot of traits, though, it is the combination of lots of genes together that result in the trait. For the second sort, you will get a mix from each parent, and are likely to have something of a blend.
That is not true. When two light skin people have kids there is even a possibility that the child will come out dark skin. In your example you say a dark skin person and a light skin person have a kid the kid will be a hue of between those shades. This is not like mixing paint. Their skin color isn’t always a hue between two parents. They can take the skin color of anybody within the family genetics. Could be a great grandmother or an aunt. Same as a child might have a nose that looks like of their aunt or great grandmother.
genes expressing themselves in a offspring depends on which gene is expressive or recessive if a expressive gene combines with a recessive gene then the expressive gene is shown in the offspring and if both the parents have recessive gene then the recessive gene will show in the offspring.
how much a gene expresses it self depends on it’s expressive or recessive-ness and it’s an intrinsic property of the gene.
here’s a helpful analogy: imagine a twin turn-table with two genes being the disks, the knob position on the slider determines the expressive-ness of the genes if the knob is in middle then both of the genes are equally expressive (you here music form both the disks equally like a child with mix skin tones) if the knob is in upper half then one gene is dominant i,e; more expressive and other the other is recessive and you here music form one disk dominating the other.
Complex traits and phenotypes are usually poly- or at least oligogenic. This means the result is governed by more than one gene. Besides that, depending on the nature of the gene products, some alleles have products that interact differently. We all know the recessive and dominant genes, but it’s more than that. The dominant we learn about in school is the complete dominant. There are also incomplete dominant and codominant genes. The former is when the two alleles mix together to produce a phenotype, like red and white mixing to produce pink flowers. The latter is when both alleles are expressed together, so red and white would produce striped petals with alternating red and white.
As I mentioned above, it depends on the nature of the product. For example, if each gene produces a different pigment but all over the petals, then when they’re different, you get a color that is a mix of the two. When each allele gets expressed in different petals or different regions of petals (due to whatever reason, too complex for this), you get stripes or some other pattern. This is extremely oversimplified, but I just wanted to give you an idea about how it can work.
Edit: English
Gene regulation also plays a part in this. Genes can be turned up and down like the volume in a speaker, and this regulation is done by other genes. For example, maybe 2 siblings inherit the same gene A from one of their parents, but sibling 1 also had gene B that amps up expression of gene A, whereas sibling 2 got gene b that doesn’t. This means that the A characteristic will be stronger in sibling 1 and not sibling 2.
It’s weird, huh? I was always curious how my mother’s red hair mixed with the darker hair of my father (i came out with dark brown hair with red highlights) when jr high genetics taught me that genes are either dominant or recessive.
Turns out, what I was taught is overly simplified at best. There are also states called incomplete dominance and co-dominance that allows for at least partial expressions of more than one gene-variant.
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