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