Are calculated genotypic frequencies necessarily the same as observed genotypic frequencies?

Mendel's Laws of Inheritance are used to calculate the phenotypic and genotypic ratios. The calculations are based on the law of probability, which assumes that all types of gametes produced by different plants have an equal chance of fusing with all other types of gametes.

The observed results will therefore be more similar to the calculated results rather than precisely the same in actual practice, as this may not always be the case.

Using a homozygous tall pea plant crossed with a homozygous dwarf pea plant, let us examine the phenomenon of pea plants.

All plants in the F1 generation are heterozygous tall, and they are permitted to freely interbreed in order to produce the F2 generation.

Male gametes carrying the T allele have an equal chance of fusing with female gametes carrying the T or t alleles. Both crossed plants produce two types of gametes: those with alleles T and t.

Comparably, there is an equal chance for a male gamete carrying the t allele to fuse with a female gamete carrying either the t or the T allele.

The F2 phenotypic ratio will be 3:1 for tall and dwarf plants in the next generation.

All dwarf plants will be homozygous dwarf (tt), so the F2 genotypic ratio will be 1;2;1. Of the tall plants, 1 will be homozygous (TT) tall and 2 heterozygous (Tt) tall.

While actual observation reveals varying ratios in various experiments, all of these will approximate the genotypic or phenotypic ratios that have been calculated.

For instance, the ratio of tall to dwarf plants that are actually produced may be 360:110, 350:110, or 355:120. These observed phenotypic ratios are all closer to the calculated 3:1 ratio than it is exact.

Comparably measured genotypic ratios are more in line with the 1:2:1 ratio.

No, calculated genotypic frequencies are not necessarily the same as observed genotypic frequencies. Calculated genotypic frequencies are based on theoretical predictions and assumptions, while observed genotypic frequencies are based on actual data collected from a population. Factors such as genetic drift, natural selection, mutation, migration, and non-random mating can all cause differences between calculated and observed genotypic frequencies.