the Gene to Geneograms
Edwin M. Knights describes one of the newer methods
of recording family data.
of family history started back in the days when cave-dwellers
began to decorate their walls with pictographic petroglyphs
portraying peripetia. Later, the nobility and wealthy families
could commission portrait painters or even sculptors to document
their importance for posterity. Clever artists usually succeeded
in giving at least a hint of the underlying personalities of
their subjects, but they risked dismissal, banishment from the
realm, or no doubt even worse fates. Even the talented Gilbert
Stuart managed to bungle a painting of Commodore Bainbridge,
giving him a shape best described as a truncated ostrich. A
subsequent unknown artist modified Stuart's work with a more
flattering physique to complement the handsome face that Stuart
"The first family records were likely recorded on cave walls, but record keeping has become more sophisticated since that time."
Having one's statue
displayed prominently has always invited attacks by unimpressed
detractors, as the political winds swirl in different directions.
President Andrew Jackson, who was also Commander-in-Chief, thought
it fitting to have his bust carved as the figurehead of America's
icon sailing ship, Old Ironsides. When the warship returned
to its home port of Boston, it was not greeted with the usual
enthusiasm. In those days, before the reign of Kennedys, the
city was a Republican stronghold and they did not appreciate
their favorite frigate being transformed into a floating advertisement
for the incumbent President. One stormy summer night the figurehead
was decapitated by an irate Bostonian wielding a sharp saw.
Fortunately for Jackson, wooden heads could be cloned.
Written family records
cover but a brief portion of humanity's existence. Prince Charles
is said to have 262,142 recorded ancestors, but even this impressive
genealogical record includes only the last 1,500 years. The
19th century seems to be the dawn of genealogy for those not
primarily concerned with royal lineage, as a new breed of genealogists
emerged, gleaning information from oral history, family Bibles
and town records. Many family trees began to sprout, illustrated
with carefully crafted charts. Folklore and tradition tended
to diminish in importance as genealogists focused on the importance
of primary documentation of evidence. In recent years, however,
more attention has been paid to recording more than just the
vital statistics. McGoldrick and Gerson probably can be credited
with introducing the term "genogram" in 1985, but similar charts
were in common use to track family medical histories well before
"A geneogram of the Kennedy family."
In 1975, Dr. Victor A. McKusick emphasized the importance of
a thorough family history in the evaluation of genetic disorders,
especially of the first-degree relatives (i.e., parents, siblings
and offspring). He divided genetic diseases into three groups:
1. Chromosomal disorders,
involving the lack, excess, or abnormal arrangement of one or
2. Mendelian, or
simply inherited disorders, determined primarily by a single
mutant gene. These can be autosomal dominant or recessive, or
they can be X-linked types.
disorders. These are caused by an interaction of multiple genes
and multiple exogenous or environmental factors. Although these
appear to run in families, the inheritance pattern is complex
and the risk to relatives is much less than the Mendelian type.
charts of these three varieties of disorders and noted differing
pedigree patterns which helped to distinguish them. They are
really little family trees, or saplings, ideally involving four
1. An autosomal dominant
pedigree (single mutant gene) shows: a) Each affected person
has an affected parent (unless it's a new mutation); b) An affected
person has equal numbers of normal and affected offspring; c)
Normal children of an affected person have only normal offspring;
d) Males and females are equally affected; e) Each sex is likely
able to transmit the condition to male and female offspring;
and f) The chart shows a vertical transmission pattern through
2. An autosomal recessive
pedigree shows: a) Parents are clinically normal; b) Only siblings
are affected; c) Vertical transmission does not occur; and d)
Males and females are affected equally.
3. McKusick also
created charts showing X-linked dominant and recessive patterns
and described patterns associated with more complicated multifactorial
genetic diseases. In the latter there is a cumulative effect
of inheriting just the right combination of genes to produce
the clinical symptoms.
By using these genograms
it's possible to predict the genetic risk within a family.
A New Tool: DNA
"Pedigrees and genograms can be made even more useful when employed in combination with DNA analysis."
Pedigree patterns and genograms assume new importance when combined
with the information becoming increasingly available from DNA
analysis. Both symptomatic and asymptomatic family members can
be checked for the presence of atypical genes, making the inheritance
pattern immediately clear. For this reason it is important to
PRESERVE DNA EVIDENCE FROM THE OLDER GENERATIONS - evidence
usually lost forever when these individuals die. DNA collections
are now easily developed from living family members. They can
be stored in refrigerated banks established for this purpose.
Or lyophilized DNA can be stored at home in contamination-proof
containers without the need for refrigeration. Fingertip blood
provides the best samples from living persons. It is also possible
to save DNA from recently deceased relatives in the funeral
home; post-mortem blood is no longer a good source for the DNA
but buccal (inside the cheek) biopsies can be collected easily
and the preservation process is the same. Of course the value
of this DNA record is not limited to currently-recognized genetic
diseases, as we are finding more and more conditions with DNA-related
factors or susceptibilities. DNA knowledge not only enlightens
us about our past - it has become a powerful tool to improve
future family health.
R. and M. McGoldrick. Genograms in Family Assessment
(New York: WW Norton & Co., 1985).
J.L. and M.S. Brown. "Genetic Aspects of Human Disease"
in Principles of Internal Medicine Ed. 8, Thorn G
et al., eds. (New York: McGraw-Hill, 1977).
E.M. "Partners in Progress: Genealogy and Molecular Genetics"
in NEXUS, Vol. 13, No. 6 (Boston: NEHGS, 1996).
E. Genograms (Chicago: Contemporary Books, 1989).
article originally appeared in our January/February 2002 issue.