The next range of questions (7-16) assess the various phenotype characteristics

Question

The next range of questions (7-16) assess the various phenotype characteristics of individuals (under the “Human Development” tab, under the “phenotype” spectrum descriptions). It may be helpful to keep track of each of these characteristics by filling out the table that is posted in your quiz description. Which of the following would be found in a person with a 46, XX karyotype without any gene mutations? [Select all that apply]

Female external genitalia

Barr body

Low testosterone, in comparison to estrogen

SRY gene

1.75000 points   

QUESTION 8

Which of the following would be found in a person with a 46, XX karyotype, with a CYP21A2 gene mutation? [Select all that apply]

Female external genitalia

Male external genitalia

Barr body

High testosterone

SRY gene

Decreased fertility

1.75000 points   

QUESTION 9

Which of the following would be found in a person with a 46, XY karyotype, with a SRY gene mutation? [Select all that apply]

Female external genitalia

Male external genitalia

Barr body

SRY gene

Female external genitalia

Barr body

Low testosterone, in comparison to estrogen

SRY gene

Explanation / Answer

ANSWER 7
The above mentioned karyotype, 46,XX actually denotes the normal karyotype of a healthy female (no gene mutation). A human contains 23 pairs of chromosomes of which the 23rd pair is the sex determining pair and is denoted as XX in females and XY in males. Thus the following would be present in such an individual.

However, the SRY gene which leads to development of male phenotypes and is present on Y chromosome is absent in females as they do not contain a Y chromosome.

ANSWER 8
46,XX is again a normal female karyotype.The CYP21A2 gene encodes the instruction for making an enzyme called 21-hydroxylase, which eventually brekas down drugs and produces certain cholestrols and hormones. A mutation in this gene in females leads to excessive built in androgens class of hormones, the testosterone. Thus the following effects can be seen-

The SRY gene and male external genetalia are cases of a male and wont be seen in this situation.

ANSWER 9-
The 46,XY karyotype is the normal karyotype of a male. The SRY gene is the male embryonic development determining gene present on the Y chromosome. Any mutation in this gene can lead to-

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