Y-Chromosome Adam?
by Dr Don Batten
Mitochondrial DNA is inherited from the mother, via the egg, and has been checked
for variations in the world-wide human population in an attempt to determine genetic
ancestry and geographic location of human origins.1
From this approach came the idea of ‘African Eve’—the hypothesis
that humans had a female parent, in Africa, and at a time so recent as to surprise
most evolutionists. Maryellen Ruvulo, using the ‘molecular clock’ hypothesis,
estimated that modern humans diverged from a common ancestor between 55,000 and
455,000 years ago.2 Of course such
age estimates depend on what rate the ‘clock’ is chosen to run at, and
that is very much determined by uniformitarian assumptions about the age of the
earth, so the molecular data are very much consistent with the Biblical model of
human origins.3
In the 1970s, Haigh and Maynard Smith investigated the variation in human haemoglobin
and concluded that the human species must have gone through a population bottleneck
in the recent past, if most of the variants are due to neutral mutations (that is,
mutations not subject to selection).4
Researchers at the University of Oregon Medical School pointed out that Noah’s
flood would have provided such a bottleneck.5
Dorit et al. recently investigated the variation in a segment on the human
Y-chromosome which is not subject to recombination, from 38 men from different ethnic
groups around the world.6 This DNA
segment was chosen because it is inherited only from the father, and, being an intron,
it is thought by evolutionists to be subject only to neutral mutations (not subject
to selection), because it does not code for a protein. Introns are commonly regarded
as ‘useless left-overs’ of evolution, so that changes in them would
not affect the viability of the individual and would not be selected against. Of
course the proposition that any DNA is ‘useless’ or ‘junk’
is highly questionable.7
Much to the surprise of the researchers, they found no variation
in the intron, which consists of 729 base pairs. They then estimated how long the
human kind could have been around since its origin, with no variation in such a
DNA segment, and estimated between 27,000 and 270,000 years, depending on what assumptions
were used in the model of population genetics. The 95% confidence intervals for
both estimates included zero years. In other words, a date of origin consistent
with Biblical chronology is within the confidence limits, even with the evolutionary
assumptions employed. Because of the lack of variation (polymorphism) the researchers
were unable to draw any conclusions about geographic origin of mankind.
The multi-regional models of human origin favoured by many evolutionists, such as
Wolpoff, are not consistent with these data. The Biblical account of a recent origin
with a single pair of ancestors, Adam and Eve, and/or a genetic bottleneck at the
time of the Flood are consistent with the above findings.
References
- Gibbons, A., 1993. Mitochondrial Eve refuses to die. Science,
259(5099)1249–1250. Return to text.
- Gibbons, Ref. 1, p.1249. Return to text.
- Wieland, C., 1993. African ‘Eve’ revived. CEN Tech.
J., 7(2):201. Return to text.
- Haigh, J. and Maynard Smith, J., 1972. Population size and protein
variation in man. Genetical Research 19:73–89. Return to text.
- Harkins, R.N., Stenzel, P. and Black, J.A. Noah’s haemoglobin.
Nature 241:226. Return to text.
- Dorit, R.L., Akashi, H. and Gilbert, W. 1995. Absence of polymorphism
at the ZFY locus on the human Y chromosome. Science 268:1183–1185.
Return to text.
- Junk moves up in the world. CEN Tech. J., 8(2):125.
Return to text.
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