Background: In a Lab that utilizes genetic crosses and observation of phenotype of offspring to predict the genotype of a parent cross, mendelian genetics and beyond-mendelian genetics must be understood.
For instance, the difference between dominant alleles and recessive allele can be determined by a multitude of ways. Often time, a genetic history is examined. If two individuals that do not express a particular trait reproduce and the offspring does express such trait, the trait is likely recessive and both parents must have been heterozygous carriers of said trait. Similarly, if both parents are homozygous recessive for an gene, all offspring would be homozygous recessive for that gene as while. If both parents were homozygous dominant, all offspring would be homozygous dominant. However, if one or more of the parents is heterozygous, offspring could express either the dominant or recessive phenotype, depending on the unique genotype such individual inherits. The ability to differentiate between monohybrid and dihybrid crosses, as well is the effect each has on an expected phenotypic ratio is also essential to this lab. A monohybrid cross occurs between two parents each heterozygous for one gene. If the gene follows complete dominance, in which the dominant
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A sex linked gene is a gene located on the X or Y chromosome. X Linked genes specifically, are located on the X chromosome. To identify whether or not a gene is x linked, a cross between a female P1 with the recessive phenotype a male P1 with who express the dominant phenotype can be used. If the gene is x-linked the phenotypic ratio for the offspring would be 1:1 for females with the dominant phenotype and males with the recessive phenotype. Any females expressing the recessive phenotype or males expressing the dominant phenotype would prove the gene to be autosomal, or non sex