Hair on human ear

I hope you have already taken the quiz published in this topic on 21st June, 2004 and are waiting to see how many of your answers are matching with the answer key.

Here are the answers - Answer key -Q 1=d, Q2=b, Q3=a, Q4=a, Q5=b, Q6=c, Q7=d, Q8=b, 9=d, Q10=c, Q11=c, Q12=b, Q13=b, Q14=c, Q15=a .

I look forward to your comments and queries on the questions and answers.
Today I shall like to discuss with you about a point in genetics in biology. It is about hair on human pinna that is the external ear.

There are some people who have a tuft of hair on their ears. You will always find them to be males and their age group will be 35 plus. Take a look at this link please, to see the character trait I am talking about - http://www.people.virginia.edu/~rjh9u/ha...

Several text books of biology at the Higher secondary level (XII) in India mention the condition as hypertrichosis and explain it is located on the Y chromosome.

The gene is reported to be present on Y chromosome ( non-homologous part ) which is present only in males. Since the gene for hypertrichosis is claimed to be present only in males it is called a holandric gene i.e. wholly andric ( male ) gene. Naturally the gene is passed on from father to son on the Y chromosome. Since only male children of a man will inherit the Y chromosome this gene follows straight inheritance that is it goes from a man to his son and then to his grandson always through the male line.

Obviously this is incorrect information in the light of new information available from human genome project. http://www.utexas.edu/courses/gene/L07.h... All modern literature as in link referred in previous line mentions only SRY gene ( Sex Determining Region on Y, earlier known as TDF, the Testicular Determining Factor )
The information about hypertrichosis gene on Y chromosome is still dished out to students by many teachers who believe what ever is in print in a text book must be true.

Parents of students even in medical and biology related fields have never raised any doubts about it.
And letters written to the authors of text books draw a blank.

Perhaps this not a unique case. In other states of India and other parts of the world such erroneous ideas are perhaps still in circulation. I shall be happy to get feedback from subject experts, teachers of biology, students currently studying and those who have passed out but continue to take interest in academics, educators and any one interested and cares about biology education.

Rarely one still get references through links discussing human hairy pinna as Y-linked trait. e.g. http://www.meredith.edu/biology/genetics...

 

The copyright of the article Hair on human ear in Human Anatomy is owned by Narayan Dattatray Wadadekar. Permission to republish Hair on human ear in print or online must be granted by the author in writing.