Monohybrid Cross - crossing one single
Trait to _______?
Answer: two alleles
To understand the concept of a monohybrid cross, we need to start with the basics of genetics.
In genetics, traits are characteristics that can be passed from one generation to another. Traits are determined by genes, which are segments of DNA that code for specific proteins. In most organisms, including humans, each individual inherits a set of genes from their parents.
Alleles are different variations of a gene. For each gene, an individual can have two alleles, one inherited from each parent. Alleles can either be dominant or recessive. Dominant alleles are expressed in the phenotype (the physical trait), while recessive alleles are only expressed if there are two copies of the recessive allele.
A monohybrid cross focuses on the inheritance of a single trait. It involves crossing individuals that are heterozygous (having two different alleles) for the trait being studied. By doing so, we can observe how the trait is passed on to subsequent generations.
For example, let's consider a monohybrid cross for flower color in pea plants. In this case, the flower color trait has two alleles, one for purple flowers (dominant allele, represented by P) and one for white flowers (recessive allele, represented by p).
When we cross two heterozygous purple-flowered pea plants (Pp x Pp), each parent has one dominant allele (P) and one recessive allele (p). The possible combinations of alleles that can be passed on to offspring are: PP, Pp, Pp, and pp.
Based on the principles of Mendelian genetics, the genotypic ratio of the offspring in this monohybrid cross would be 1:2:1, meaning that for every one PP genotype (homozygous dominant), there would be two Pp genotypes (heterozygous) and one pp genotype (homozygous recessive).
So, in summary, in a monohybrid cross, we are crossing individuals with two different alleles for a single trait to study how those alleles are inherited by the offspring.