Human Growth and Development

Genotype vs. Phenotype ●​ Genotype: A person’s genetic code , including dominant and recessive genes. ●​ Phenotype: The observable traits , like eye color, hair color, and height. Carriers and Genetic Interaction ●​ Carriers: People who have a recessive allele that isn’t visible in their traits but can be passed to offspring (e.g., cystic fibrosis carrier). ●​ Gene-Gene Interaction: Some traits result from multiple genes working together. ●​ Gene-Environment Interaction: Genes can be influenced by external factors like diet, stress, or exposure to toxins. Gene-Gene Interaction

Gene-Gene Interaction

Example

Additive shows the contribution of multiple genes.

A tall woman and a short man have a child of medium height. A person with a dominant brown eye gene can carry a recessive blue eye gene, but brown eyes will usually be expressed due to the dominance of the brown gene. Some red flowers and white flowers may produce pink flowers in a variety of pink hues. Baldness in men is carried on the X chromosome.

Dominant-Recessive: Genes are non-additive, meaning they are one or another.

Incomplete Dominance: Phenotype is not entirely controlled by the genotype.

X-Linked Genes: Genes on the X chromosome can be dominant or recessive and are more common in men.

Polygenic traits: Traits influenced by more than one gene.

Height and skin color.

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