<Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2009) (Learn how and when to remove this template message) </Td> </Tr> <P> A monohybrid cross is a mating between two individuals with different variations at one genetic chromosome of interest . The character (s) being studied in a monohybrid cross are governed by two or multiple variations for a single locus . A cross between two parents possessing a pair of contrasting characters is known as monohybrid cross . To carry out such a cross, each parent is chosen to be homozygous or true breeding for a given trait (locus). When a cross satisfies the conditions for a monohybrid cross, it is usually detected by a characteristic distribution of second - generation (F) offspring that is sometimes called the monohybrid ratio . </P> <P> Generally, the monohybrid cross is used to determine the dominance relationship between two alleles . The cross begins with the parental (P) generation . One parent is homozygous for one allele, and the other parent is homozygous for the other allele . The offspring make up the first filial (F1) generation . Every member of the F1 generation is heterozygous and the phenotype of the F1 generation expresses the dominant trait . Crossing two members of the F1 generation produces the second filial (F2) generation . Probability theory predicts that three quarters of the F2 generation will have the dominant allele's phenotype . And the remaining quarter of the F2s will have the recessive allele's phenotype . This predicted 3: 1 phenotypic ratio assumes Mendelian inheritance . </P> <P> This cross was originally used by biologist Gregor Mendel, who crossed two pea plants to obtain a hybrid variety and discovered the dominance relationships between alleles of several genes . </P>

The first generation in a series of monohybrid crosses is referred to as the ___ generation