* Zygote: A zygote is the first cell of a new organism, formed when a sperm cell fertilizes an egg cell.
* Alleles: Alleles are alternative forms of a gene. Each gene resides at a specific locus (location) on a chromosome.
* Inheritance: Each parent contributes one chromosome from each pair to their offspring. This means the offspring inherits one allele for each trait from their mother and one allele from their father.
Here's an example:
* Trait: Eye color
* Gene: The gene responsible for eye color.
* Alleles: There are multiple alleles for eye color, but let's say the mother carries the allele for brown eyes (B) and the father carries the allele for blue eyes (b).
* Zygote: The zygote will receive one allele from the mother (B) and one allele from the father (b). The zygote's genotype for eye color will be Bb.
How the offspring's trait is expressed depends on the specific combination of alleles (genotype) they inherit:
* Dominant allele: If one allele is dominant, it will mask the expression of the recessive allele. For example, brown eyes (B) might be dominant over blue eyes (b), so a zygote with Bb genotype will have brown eyes.
* Recessive allele: A recessive allele will only be expressed if two copies of the same recessive allele are present. In the eye color example, a zygote with bb genotype would have blue eyes.
In summary: The alleles for any trait in a zygote come from the mother and father, ensuring that the offspring receives a unique combination of genetic information from both parents.
