Mendelian Genetics (Monohybrid Cross)

In order to do Mendelian genetics problems, we must understand these two laws.

• The principle of segregation (First Law): The two members of a gene pair (alleles) segregate (separate) from each other in the formation of gametes. Half the gametes carry one allele, and the other half carry the other allele.
• The principle of independent assortment (Second Law): Genes for different traits assort independently of one another in the formation of gametes.

In a monohybrid cross, we analyze organisms with one trait. Let's take the color of fur on a type of bear for example. The black fur is the dominant trait, and the brown fur is the recessive trait. B and b are alleles respectively for each trait. We can have combinations of different types of bears (homozygous dominant, heterozygous dominant, and homozygous recessive)--(BB, Bb, bb). When two bears cross, they form gametes by assorting the alleles independently according to the Mendelian laws.