Which gene is responsible for the inheritance of toe and fingerprints? The Genome study announced in February 2001 that there are only about 30,000 human genes responsible for our inheritance, not 100,000 as was previously predicted. The remaining 70,000 are relics of our evolutionary past, dubbed in U.S. colloquialism, 'junk genes'. The maximum difference in human D.N.A. is only 0.5% [about 15,000 CGTA units] there would be even less between members of a shared family name.
More recently the misnomer 'junk
genes' has been blasted apart by the finding that they are in
fact not 'junk'. The 70,000 genes not in regular use by the
body cells in fact contain 'genetic switches' that can turn
specific active genes 'on or off'. These 'epigenetic
switches' may hold the key to solving some of the genetic
diseases that afflict all living things. If we read the human
genome like a book we recognise that there are print errors
that equate to gene changes/errors that lead to natural
selection by the environment.
Surnames are far more resilient than genetics
As each generation passes, the number of chromosomes inherited from a
particular individual is reduced by half whilst the number of predecessors
doubles. As a consequence, the number of genes is also halved from any specific
parent. The reduction occurs like this:
Generation |
No. of genes |
No. of predecessors |
Parent |
30,000 |
- |
F 1 |
15,000 |
2 |
2 |
7500 |
4 |
3 |
3750 |
8 |
4 |
1875 |
16 |
5 |
~938 |
32 |
6 |
~469 |
128 |
7 |
~234 |
256 |
8 |
~117 |
512 |
9 |
~59 |
3584 |
10 |
~29 |
7168 |
11 |
~15 |
14336 |
12 |
~7 |
28672 |
13 |
~4 |
57344 |
14 |
~2 |
114688 |
15 |
~1 |
229376 |
16 |
- |
458752 |
Thus for any specific predecessor, after 10 generations [or about 250 years]
approximately 29 genes remain from that particular person [obviously the
remainder of the chromosomes are composed of genes from the multitudes of
other predecessors]. Thus although we may see that we are descended from a
particular person, most of the genetic change or loss has occured in the first
few generations so that by the 15th generation [~ 400 years] there is actually
very little genetic material remaining [< 3.33 x 10-4 %] from
the specific predecessor. At the same time we are seen by positive exponential
growth to be descended from almost a quarter of a million predecessors. Certainly,
an inherited surname possesses a much longer 'shelf- life' than the genetic
material from a single predecessor. We are indeed unique and composed of
the genetics of many persons who have gone before and will with luck, follow
us. That is the much sought after 'everlasting life', we already have it.
Today: Life expectancy in Western Societies averages 76 times around the sun for males and 82 for females. 75% of centenarians are women. |
Martha Meakin [nee Midgley] of Normanton, West Yorkshire is the oldest
Midgley at 104 years [2001] whom I have become aware of, can anyone
substantiate a longer lived Midgley?
Contact through guestbook on main
page
|
We know there are many traits and even diseases which "run in families". Studies at the University of Newcasle, N.S.W. have indicated that a person's intelligence can be the result of a gene carried on the female X chromosome.
Males possess a mixture of X & Y chromosomes as the 23rd pair (sex
chromosomes) whereas females have a pair of XX chromosomes. This
indicates that when a male inherits intelligence, if his mother passes
this on from his grandmother then he is likely to have the grandmother's
intelligence gene.
The mother may not have the phenotype for her mother because
she is also carrying the second X chromosome which may positively
or negatively reinforce the the gene in the first X chromosome inherited.
Males have a slightly higher chance of having intelligences from the
extremes of the distribution curve because they only inherit one X chromosome.
This conforms to known distributions of I.Q. for males and females
which shows more males having very high and very low I.Q's compared
to females, but more females outperform males in the mid-range. Gentlemen,
before you procreate check the intelligence of your mother-in-law!
Like males, females can still get very low and very high I.Q's but there are fewer at the extremes of the distribution curve compared to the average male.
From a study of twins it appears that I.Q. is about 80% nature and 20% nurture. The late Prof. Max Eysenck (L.S.E.) strongly argued for a genetic basis to human personality and behaviour but his work was seen as highly contentious. We can inherit haemophilia, a sex linked blood disease carried on the female chromosome which only affects males, so we may ask the question why do we revile from inheritance of intelligence? Is it that I.Q. is not seen as a tangible entity but a human concept and very limited in what it measures? Recent genome studies indicate this hypothesis is now much maligned, it appears that intelligence (as measured by I.Q.) is a result of a combination of genes.
There are now considered to be multiple intelligences such as
:
numerical
spatial
language
musical
visual
auditory [some people are good listeners]
interpersonal relationships
intrapersonal relationships
kinesthenic [learning through moving or doing]
calisthenics (e.g. dancers, wood turners)
Intelligence Quotient tests tend only to examine the first three "intelligences"
and hence its demise as a tool of measurement in education. This
fits better with the "Outcomes" approach to education where students
are recognised to have specific abilities. These intelligences are likely
to be carried in families and again a gene or group of genes may
be responsible, if they are sex linked then this would give genealogists
something else to think about.
The human genome project which mapped 3.1 billion
CGTA combinations
was essentially completed a few years ago, this search provided us
with more information about what our real inheritance is. Reports in November
1999 indicated that a U.S. commercial company trying to make monetary
gain by identifying the human genetic code with the aid of a super-computer
gene sequencer, claimed it could achieve in less or the same time what
the U.S.-U.K. genome project would achieve. The difficulty appears to
be that it would not seem possible to patent parts of the human genetic
code even though it was not invented by anyone or any group. The written
CGTA code was like
a book published in a hurry, there were "spelling mistakes" in the
code and "pages" were missing. In 2001 the "slower" but more complete
method of uncovering the human genome was jointly announced alongside
the commercial venture, by William Clinton in the White House.
Some believe genetic inheritance is eternal life, "The meaning of life"
as we each live on through our genes, whilst the $10 worth of
chemicals we have borrowed for 70 years is used to transiently hold
those genetic codes and is recycled through ecological systems. Isn't life
clever! An island of order in a sea of chaos.
Key: X =female sex chromosome -chromosome carrying gene for intelligence (I.Q.) Y= male sex chromosome |
Parents (P1) : X1 Y1 x X2X3
First family (F2) :
X1X2, X1X3, Y1X2, Y1X3
we can see here that the male Y1X3 mix is carrying only the intelligence gene in the X3 chromosome whilst the female X1X3 carries a mix of intelligence genes from the father's mother and the mother's mother.
In the next sequence notice how the female X chromosome brings other genetic material to the male, it appears that the female chromosome brings variety to an unchanging male Y chromosome (supposing no mutations occur).
P1: X1Y1 x X2X3
P2: X1Y1 x X4X5
F2: X1X4, X1X5, X4Y1, X5Y1.
P3: X5Y1 x X6X7
F3: X5X6, X5X7, X6Y1, X7Y1
If the children do well it must be genetic,
if they don't, it must be their teachers!
Thus geneticists tell us that when males choose a future partner it is more advantageous if they choose an intelligent female to ensure their offspring have a higher chance of being more intelligent. Looks are fleeting, genetics are forever.
DNA
clues at scene can name criminals/families
DNA found at a rape or murder scene could soon
be used by police
to trace the surname of the criminal. He said it meant most families had a single founder whose Y chromosome pattern had still survived. "If you have a more common name, such as Smith or Jones you might find several founders, but most people have relatively rare surnames and I suspect for them there is only a single founder." The discovery, published in this month's issue of the American Journal
Human Genetics, was so significant it was already the subject
of a worldwide patent. |
What's in a name?
Recently, a very rare Y chromosome was found in a Yorkshireman
living in Leicester. This Y chromosome was previously found only in West
Africa. The survey of 150 pairs of men focussed on their shared
surname, e.g. Smith-Smith, Jones-Jones etc. These pairs of volunteers
were not known to have a shared ancestry.
Their Y chromosome was analysed and then each was compared. Only
25% of this sample showed a common ancestry through their Y chromosome
and thus a shared common ancestry. Removal of high frequency names such as
Smith increased the chance of sharing ancestry to 50%. and when the test
was applied to rarer names this increased to 80%. As research continued
into this common ancestry a eureka moment was experienced when a rare West
African Y chromosome was discovered, previously only known in 25 African
people in West Africa.
After this discovery the researchers, Professor Jobling and Turi
King of Leicester University, collected D.N.A. from 18 men with the
same surname [Revis] as that of the man with this rare Y chromosome. They
then found that 7 of them also shared this rare Y chromosome. The men were
all Caucasian and had no known African ancestry. The original man found
to have the West African Y chromosome traced his ancestry back to the mid
1700's and could not find any ancestors of African origin.. Further research
'paper-trailed' the chromosome back to two family trees in Yorkshire from
1780.
There are two hypotheses as to how this chromosome entered Britain:
1. The Romans brought soldiers from North Africa about 200 A.D.
2. Via the slave trade. In the late 1700's there were about 10,000
Africans residing in the U.K.
Prof. Jobling states that " This research raises the possibility
of tracing surnames back to single founders, and of linking together branches
of family trees by the information written in D.N.A., rather than B.M.D.
certificates." The level of illegitimacy indicated by the genetic study
shows a rate of about 1%, not the generally 10% suggested by traditional
genealogy.3 See Midgley D.N.A.
Mitochondrial D.N.A. and gene mapping:
Oxford Ancestors#- A commercial site where you
can have your D.N.A. mapped, by Prof. Bryan Sykes' team to find out
:
1. if you have Viking ancestry
2. if you belong to the same Midgley branch as someone else
[by comparing your profiles]
3. which of the "Seven daughters' of Eve" you are related to!
Prof.
Bryan Sykes' family tree is crossed with some of the Midgley branches
in West Yorkshire.
"On the morning of the 10th September 1984 Alec Jeffreys
stumbled upon DNA profiling, identifying the patterns of genetic material
that are unique to almost every individual. The discovery revolutionized
everything from criminal investigations to family law. Jeffreys is
still awed, and a bit worried, by the power of the technology he unleashed
upon the world. “I think there are potentially major issues about genetic
privacy,” Jeffreys said in September 2004 at a press briefing to mark
the 20th anniversary of the discovery.
In the November 1999 issue of Science the Whitehead Institute in Massachusetts sets out the case for the diminishing Y chromosome. The institute traced the divergence of the X and Y chromosome.The earliest, and todays simplest plants and animals show no male/female characteristics. This divergence began about 320-240 million years ago and is continuing today.
Like many genetic changes it began with a random mutation on the proto-Y
chromosome which continued with punctuated evolution ("jumps") until
today.
The modern X chromosome has about 10 times more genes than
a modern Y chromosome which has been casting off genes that are not
useful to the male for the last 320 m.y.
Each Y contains the SRY gene which is the master-switch
for maleness in all plants and animals which reproduce by sexual methods,
i.e. two distinct specialised reproductive cells.
Epigenetic switches & how your life experiences may affect the future genetics of your descendants and how you too may have been affected by your predecessors...... Studies of families over several generations within isolated communities have shown a pattern which supports the theory of genome imprinting. That is, the life experiences of the grandparents &c. may have implications for future generations in up to 80% of individuals. For example if a grandparent is exposed to famine, a particular pesticide or other organic molecule not usually found within the body, the offspring of future generations may be affected by the experience of the ancestor. This has dire implications for those whose predecessors may have been exposed to severe stress situations, psychotropic [mind-altering] drugs, even smoking tobacco or excessive consumption of alcohol.
Since the human genome has been revealed by geneticists it has been realised that the ~30,000 genes that are actually active are insufficient to account for the complexity of the species [grasses for example have more genes than we do]. Research using many generations of mice supports the theory of genome imprinting where genes may be switched on or off by a controlling environmental factor. This is an added complexity to the previously recognised mechanical inheritance of genes.
The critical times when predecessors may be affected by their environment is an important part of the inheritance of epigenetic switches. In males the sensitive or critical time for exposure is just before puberty when the sperm cells are beginning to develop. In females, the critical time is at their conception and shortly thereafter when the immature ova are formed.
The increase in the use of mind-altering drugs in recent generations may have far reaching effects into future generations, far beyond the individual who originally ingested them. This is another good reason to choose your parents and your partner very carefully.
These so-called epigenetic switches are in fact methyl groups [-CH3] that are attached along different parts of the DNA molecule. It seems that these methyl groups can turn specific genes along the DNA molecule on or off in a similar way that the binary code operates in a computer. Depending on the location of these methyl groups a person may suffer from such debilitating inherited diseases such as Parkinson's Disease or Schizophrenia. Methylation may also be found to control whether a person is heterosexual or homosexual. The study of epigenetics is an enormous area for future research and is likely to lead to a better understanding of how our genes may be modified and hopefully solve some of humanities major debilitating diseases.
< Methyl groups attached to a part of a DNA molecule thus modifying the effect of the genes ('rungs' of the ladder)
Archaea and bacteria
Primitive organisms called archaea and primeval bacteria have been fingered for beginning the complexity of life. Archaea are believed to have engulfed early bacteria in order to assist in the formation of mitochondria, the energy source for cells. The study of archaea show that humans share 200 genes with modern forms of Archaea, indicating a common origin. The sea worm Amphioxus, led to the vertebrate structure, again the amphioxus genome lies within our own genome leading to a four-fold structure for vertebrates. Further studies have shown that on chromosome No. 7 there is a gene for seeing the colour blue while the X chromosome carries the gene for seeing red and green.
Differences between humans
There is only 1 in 1000 genes difference between each person, thus of the 30,000 active genes there are a maximum of 30 genes difference.
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