Investigation 3: Mapping Mutations: Sex-reversal and other deleterious mutations of the SRY
gene in humans
What happens when there is a mutation in a gene? One of the resources available at NCBI is a
database of mutations in human genes and the outcomes of the mutations. Most of these
mutations are associated with diseases or disorders. This database is called Online Mendelian
Inheritance in Man (OMIM). OMIM contains information about all known human Mendelian
disorders, and is used by genetic researchers, physicians and other professionals concerned with
genetic disorders, and students in science and medicine.
From the NCBI Entrez Gene page for SRY, navigate to the Online Mendelian Inheritance in
Man (OMIM) by clicking the OMIM link on the right side of the page under the heading
“Links”.
This connects to the record in the OMIM database for SRY: *480000 SEX-DETERMINING
REGION Y; SRY. Note the cytogenetic location of SRY, previously discussed in Investigation
2.
Next, click on the record link, *480000
Answer the following questions in your laboratory notebook in the “Answers/Conclusions”
section:
Question 3-1: According to the Description, what is the function of the protein produced by
SRY?
Question 3-2: In Mapping, how was the TDF/SRY gene ultimately mapped to the Y
chromosome?
Allelic Variants of SRY
Question 3-3: Using the information provided in the Allelic Variants section, explain how an
individual with an XY karyotype could have a female phenotype.