Sep. 21. 2023

Making a Baby: Understanding Genotypes, Phenotypes, and Human Reproduction

This article delves deep into the scientific journey that unravels the mysteries of human genetics, exploring the intricate interplay between genotypes and phenotypes in the context of reproduction. Together, we'll delve into the fundamental genetic principles that shape the unique traits and characteristics of every individual, and gain insights into the awe-inspiring process of human life creation.

How does the combination of genetic codes and biological processes orchestrate the miraculous transformation from two sets of DNA into a single, extraordinary human being? 

Every trait is governed by a pair of genes, one inherited from each parent. Within each gene, there exist two allele variations: dominant and recessive. When inheriting traits, they can manifest as two dominant alleles (YY), two recessive alleles (yy), or one of each (Yy). Importantly, the allocation of dominant and recessive genes from parents to offspring is entirely dictated by the element of RANDOM CHANCE.

A genotype is like the recipe for a trait, showing which genes and versions (alleles) are involved. It's the behind-the-scenes genetic makeup. Phenotypes are what actually show up or appear in a person. They are the visible or observable results of that genetic recipe. It's what you see on the outside, like your eye color or hair type. It's the product of the recipe; the big mac, the sandwich we see, or that one delicious pizza that's been served.

Homozygous means having a genotype with two identical alleles, like having two copies of the same genetic ingredient. Two dominant alleles result in showing the dominant trait, which is the characteristic that stands out strongly. Two recessive alleles lead to displaying the recessive trait, which is the feature that's less noticeable when both ingredients are the same. Heterozygous is when the genotype has one of each type of allele, like having one of each ingredient.

A dominant trait is an inherited trait that shows up in the offspring. Offspring, meaning a persons child or children (plural). Recessive traits are inherited traits that show up in the offspring only if both parents passed on the genes for the trait. For example, consider the trait of brown eye and blue eye, with brown eye being dominant and blue being recessive. Recessive traits are inherited traits that show up in the offspring only if both parents passed on the genes for the trait.If one parent has a genotype of BB (two dominant alleles for brown eyes) and the other parent has a genotype of bb (two recessive alleles for blue eyes), the offspring will inherit one allele from each parent.  If the child inherits one B allele (brown) and one b allele (blue), the dominant brown trait will be expressed in their phenotype, and they will have brown eyes. In this case, the dominant trait (brown eyes) shows up in the offspring, as at least one dominant allele is present.

Now, with the general information out of the way, let's make a baby.

A trend that I personally notice is how different we all our in our own unique ways. That's great; supporting diversity, equity, and inclusion should be a priority for all schools and organizations. While most people have brown eyes, straight hair, and black / brown hair since these are the most dominant traits, people also have a variety of curly hair, blue eyes, green eyes, etc. Some traits are more common than others. Each person's DNA is a unique combination of genes inherited from their parents. Genes contain instructions for various traits, including physical characteristics, susceptibility to certain diseases, and more. We all come from different families, heritage, and places in the world. For example, Asians may have smaller eyes. It's not a stereotype, but it's a fascinating adaptation that we've developed as a of result to brighter climates. Our bodies have evolved differently compared to others, and that's what makes humans fascinating species.

Genotypes are the underlying genetic compositions that give rise to our observable phenotypes, determining their characteristics. For instance, in my character's case, their male identity is established by the presence of XY chromosomes, while their possession of a pointy nose can be attributed to a dominant genetic trait specifying the shape of their nose. Phenotypes on the other hand is the result / product of the genotype type. For example, having the genotype "XX" gives you a phenotype of being a female. Another example is that having the genotype "RR" for a specific gene can result in the phenotype of having freckles, as "RR" is associated with the dominant trait for earlobe attachment. Dominant traits are genetic characteristics that are expressed or observed in an individual's phenotype when only one copy of the associated allele is present. Recessive traits, on the other hand, require two copies of the associated allele to be expressed in the phenotype. When a dominant allele and a recessive allele are present together, the dominant trait typically prevails. For example, although I had the genes "Aa" (A for having a round face, a for having a square face), A is more domiant than a, automatically giving me the phenotype of having a round face.