Question

Eye color is an inherited trait. Your genes come from your mom and dad, and more specifically from the sex cells that they produce. Please answer the following questions related to determining eye color. In the human life cycle, gametes (or sex cells) fuse through a process called fertilization. When the gametes (or sex cells) fuse, the plasma membranes of those cells fuse, the cytoplasmic contents come together, and the nuclear membranes with all of the genetic material they contain fuse as well. The DNA is organized in linear chromosomes in our nuclei, and when the gametes fuse, the set of chromosomes you inherit from mom come together with the set from your father. These "sets" of chromosomes are called homologous pairs. These "sets" of chromosomes are not identical but do contain information for similar genes at specific locations on the chromosome. Genes are segments of DNA that encode specific proteins or RNA. The way we inherit some traits like "Widow's peak" is simple in that there are 2 possible genes, and we either inherit two copies of the gene for + Widow's peak, 2 genes for - Widow's peak, or one of each, and there is a clear result in the phenotype (expression of the gene combination) that results.

Part 2 Directions: Answer the question below in 2 to 3 well-structured paragraphs. Remember that a well-structured paragraph consists of at least 2-3 full sentences and conveys a distinct thought or theme about the subject. For some traits, there is a clear result in the expression of the gene combination. For other traits like eye color and skin color, the end result is more complex. How is a trait like eye color more complex than something like a Widow's peak?

Answer 1

Eye color is more complex than traits like a Widow's peak because it is a polygenic trait, meaning multiple genes contribute to the final color, allowing for a wide variety of phenotypes. A green-eyed child of brown-eyed parents suggests that both parents were heterozygous for the eye color gene, each carrying an allele for green eyes.

Step-by-step explanation:

Eye color inheritance is a complex trait, involving multiple genes rather than a single gene, as is the case with simpler genetic characteristics like a Widow's peak. Unlike simple Mendelian traits, which are determined by a single gene with clear dominant and recessive alleles, complex traits like eye color are influenced by the interaction between various genes and their alleles. This polygenic type of inheritance means a combination of several genes contributes to the phenotypic expression of eye color, causing the wide spectrum of colors we observe in human eyes.

In the case of two brown-eyed parents producing a green-eyed child, the genetically possible explanation is option (b): Both parents are heterozygous, having the green trait on the green-blue eye gene. This means each parent carries one allele for brown eyes and one for green eyes, and both happened to pass the green allele to their child. Due to the complex nature of eye color genetics, the combination of non-brown alleles managed to express as green in the child, since green is a recessive trait in comparison to brown but can still be expressed when the dominant brown allele is not present from either parent.