Discovery of the “Bald” Gene: Popular Press vs. Scientific Literature

This web page was produced as an assignment for an undergraduate course at Davidson College.

Introduction:


Almost everyone seems to know someone who has been overwhelmed by baldness early in life. However, with the recent entrance of two drugs, Rogaine and Propecia, many people have found an answer to hair loss. So, how can genes related to baldness help the public? Moreover, can gene therapy accurately replace the success that new drugs have brought to the market? For now, the answer seems to be no. During the course of this web page, I will discuss differences between a popular press article and a scientific journal concerning the discovery of one bald gene. In 1998, Science magazine published an article by Dr. Angela Christiano concerning the unearthing of one gene related to a certain type of baldness. In the past, balding disorders were known to be hereditary though no research was able to pinpoint any exact genes. Until Dr. Christiano’s discovery of the human hairless gene related to Alopecia Universalis, no genes had been found that were responsible for baldness. Popular

Press Report:

CNN.com

Summary:

On January 29th, 1998, CNN reported that a team of researchers led by Dr. Angela Christiano discovered the gene responsible for Alopecia Universalis. This genetic disorder causes complete hair loss just following birth. According to CNN some 52 million citizens of the US endure hair loss during life. With the mapping of the “hairless” gene, researchers should have the possibility to find other hair loss genes and treatments for baldness. Dr. Christiano is optimistic that her research will lead to further discovery of unknown hair loss genes as well as treatments or cures for baldness.


Scientific Journal:

Science

Summary:Introduction

On January 30th, 1998, a team of researchers led by Dr. Angela Christiano of Columbia University published an article on the human hairless gene, a gene they claim that is directly responsible for Alopecia Universalis. In this case, the discovery of a gene linked to Alopecia Universalis means that at least one gene has been found that is linked to some type of baldness. Bald disorders are referred to as alopecias. Each of the affected family members had a missense mutation (Ahmad W, et al. 1998). This missense mutation helped Christiano and her researchers identify the gene. A missense mutation is a base substitution that changes the genetic message so that when a new amino acid substitutes in a protein, the function of the protein is changed (Purves et al. 2001).


Alopecia Universalis


Alopecia Universalis is the most extreme of all the alopecia diseases. This disease is characterized by the complete absence of scalp and body hair (Ahmad W et al. 1998).


Research


All of the individuals that were used in the research were from a Pakistani family who exhibited “a single Mendelian abnormality without associated ectodermal defects,” meaning no outward skin defects were visible on any of the individuals. The study involved four males and seven females, all were affected individuals in good health. All of the individuals were homozygous recessive for Alopecia Universalis (Ahmad W et al. 1998).
During the experimentation, Dr. Christiano and her group of researchers used radiation hybrid mapping to find the hairless gene. First, they performed a genome search for linkage via homozygosity mapping. After using DNA samples from four individuals, 13 genomic regions were found that were ”homozygous for three to four affected individuals.” Finally, 12 of the regions were excluded when 32 additional family members were tested. One marker in the remaining genomic region, “D8S136 on chromosome 8p12, was found to be homozygous in all seven living affected individuals.” More testing showed that two other markers were homozygous in the affected individuals. These two markers were D8S298 and D8S1786. Through more statistical testing and computer work, the group was able to determine that the alopecia gene in the affected family “maps to chromosome 8p12” (Ahmad W et al. 1998). Now, the group moved in another direction. Using reverse transcriptase PCR (polymerase chain reaction), the group looked at two particular segments of the human and mouse “hairless” gene. “Using human skin fibroblast mRNA as template” the group “delineated the entire coding sequence of human ‘hairless’” (Ahmad W et al. 1998). The hairless gene was a total of 1189 amino acids in length. Next, “radiation hybrid mapping” was employed to “determine the precise chromosomal localization of the human homolog of hairless” (Ahmad W et al. 1998). Once the location was confirmed on chromosome 8p, the group hypothesized that the hairless gene was responsible for Alopecia Universalis. Using “direct sequence analysis” the group determined that the missense mutation was an A to G base transition and was present in all the affected individuals. This base substitution caused alanine to be translated instead of the normal amino acid threonine. This different amino acid resulted in “a new cleavage site for the restriction endonuclease Hga I.” This transcription factor, the restriction endonuclease Hga I, was thought to be the major reason for the loss of hair since fibroblasts in human skin were directly affected by the AU mutation. Additionally, the group added that other genes that affected transcription factors were responsible for hair loss. Therefore, the group concluded that it was possible that the AU mutation disrupts the hairless gene and causes hair loss.Discussion:
The major differences between the CNN article and the Science article involve their presentation of the discovery of the gene. CNN hopes to sensationalize the discovery of the gene by making predictions about how this gene could lead to the curing of baldness. Though the CNN report seems to present just the facts about the research, the reader is able to detect a more sensationalistic connotation in the article. In contrast, the researchers approach their topic with much more caution about treatments or cures. At the end of their article, Christiano and her group explain that more research into the human hairless gene could “illuminate potential therapeutic opportunities.” This statement is somewhat contradictory to what CNN reports. CNN seems to find more room for discussion about cures and treatments. For instance, CNN closes their article with a statement by Christiano herself that seems somewhat optimistic about hair coloring and baldness treatment. Christiano says, “It is now within our reach to design ways to grow hair, remove hair, even dye hair genetically.” This statement seems to suggest that the cure for baldness will be in pharmacies very soon. Another somewhat optimistic statement by CNN is that finding genes for hair loss “could lead to other advances,” as well as a cure for some types of baldness. CNN tries not to overstep the bounds of what Christiano and her group accomplished. At times, it seems that CNN stretches for more sensationalistic comments in order to enliven their article. In conclusion, for CNN the most important part of their article is to suggest to the reader that cures and treatments for baldness are just around the corner. In reality, Dr. Christiano and her group have only reported on one human gene that is responsible for a specific type of baldness. In the future, the cure for male pattern baldness disease may be found using steps learned by Christiano’s group.

References:

Salvatore S. 1998 Jan 29. Home page. <http://www.cnn.com/HEALTH/9801/29/baldness.gene/index.html>. Accessed 2003 Sept 12.

Ahmad W, Faiyaz ul Haque M, Brancolini V, Tsou HC, ul Haque S, Lam H, Aita VM, Owen J, deBlaquiere M, Frank J, Cserhalmi-Friedman PB, Leask A, McGrath JA, Peacocke M, Ahmad M, Ott J, Christiano AM (1998) Alopecia Universalis Associated with a Mutation in the Human hairless Gene. Science 279: 720-24.


Purves et al. Life: The Science of Biology, 6th ed. WH Freeman Co., 2001. Back to Home Page

 

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This web page was produced as an assignment for an undergraduate course at Davidson College.