What is a locus?

• A. A structure that appears during prophase I and consists of two paired genes
• B. The precise DNA sequence of a gene
• C. A type of spore made only by fungi
• D. A cell with two chromosome sets
• E. The precise location of a gene on a chromosome

Answer: (E)

Verified step by step guidance

1. Understand that a locus is a term used in genetics to describe a specific location on a chromosome.
2. Recognize that each gene occupies a particular locus on a chromosome, which is its precise position.
3. Differentiate between the term 'locus' and other genetic terms such as 'allele' (which refers to different versions of a gene) and 'gene' (which is a sequence of DNA that codes for a protein).
4. Remember that the locus is not about the sequence of the gene itself, but rather the position where the gene is found on the chromosome.
5. Note that the concept of a locus is fundamental in understanding genetic mapping and inheritance patterns, as it helps in identifying where genes are located on chromosomes.