How Meiosis Models Mendel’s Observations
Mendel’s experiments with pea plants revealed how traits are inherited through
discrete units called genes. The process of meiosis, discovered later, provides the
biological explanation for Mendel’s laws.
1. Mendel’s Law of Segregation
Mendel’s observation:
Each organism has two alleles for a trait, and these alleles separate during gamete
formation — so each gamete receives only one allele.
How meiosis models this:
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During Anaphase I of meiosis, homologous chromosomes separate, carrying
different alleles of a gene to opposite poles.
Thus, each gamete gets only one allele for each gene.
This explains why offspring receive one allele from each parent.
2. Mendel’s Law of Independent Assortment
Mendel’s observation:
Alleles of different genes are inherited independently of one another (if they are on
different chromosomes).
How meiosis models this:
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During Metaphase I, homologous chromosome pairs line up randomly at the
cell’s equator.
The orientation of one pair is independent of others.
This random alignment leads to many possible combinations of maternal
and paternal chromosomes in gametes.