Statistical theories of ancestor numbers

We all have ancestors and statistically speaking, if we go back far enough through the generations, we will find a lot of farmers, miners and ne’r do well predecessors. And maybe also someone of particular note, Lords, Ladies, National heroes, musicians or maybe Kings or Emperors. These were the celebrities of ancient times.

A leading exponent of the statistical theory of population ancestry Professor J T Chan has developed numbers that have been widely accepted as a theoretical model. He concludes that statistically everyone in a specific region (e.g. continental Europe) is to an extent related to each other. We all carry a % of ancestors DNA.

Chang states that each generation provides the possibility of 4 grandparents. When calculated with each generation that results in 2 parents and 4 grandparents.

Calculated exponentially, 10 generations back there would be over 1,000 super grand relatives, often expressed as 8th Great Grandparents.

After 20 generations we would have over 1 MILLION super grand relatives.

Go back 40 generations (1200 years) and you will find over 1 trillion super grand relatives, more than the population of Europe has or can ever have!

All this makes mathematical sense but 1 trillion relatives? Simple science and common sense makes us question this theory. With each generation our extended family increases in width, but our direct generation by generation bloodline ancestors is much less affected. Also consider that like the while mankind developed and mutated it also appeared, like the invention of the wheel, in multiple places. This leads us into a revolving and contentious argument.

The American Museum of Natural History

The American Museum of Natural History population model which has the WORLD population reaching 360 million just after the year 1200 then falling back to 350 million by 1400 following the great plagues (the only time the world population has declined).

EUROPE is around 10% of the world population, so for year 1200 it would have been standing at around 36 million.

Chan’s model for the European population is out by a factor of 3,000, an error rate of over 99%, clearly unreliable for any purpose other than a mathematical model. .

By 1700 and the Sophie Succession the WORLD population was reaching 600 million, (going back 8 generations back in the Low-ancestry).

From 1700 to 1800 the World population was raised to 1 billion and by 1900 1.6 billion. World population is estimated to be around 6.5 billion by the end of 2020.

In 2011 Europe remained around 11% of the world population (and falling) so a fair estimate of the European population in 2020 would be 10% of 6.5 billion, so in round terms 650 million.

It took 200,000 years for the human population to reach 1 billion but only 200 years to reach 7 billion. Since the end of WW2 the population had increased by 500%.

So how do we moderate and make sense of Chan’s theory? What are the variants and what are the more realistic and predictable possibilities? Let’s work from the back to the front of the queue of these statistical relatives and understand why in reality the numbers must be realistic. .

20% of the mature population do not create children.

The rates of infant mortality and/or birthing mother death during or shortly after childbirth increase significantly the further back we look.

During the middle ages and well into the early 19th century childhood death rates were high, frighteningly and commonly extremely high. The 20th century with social and medical improvements and developing living habits saw a reduction in birth, infant and childhood survival rates.

There are a lot of shared cousins out there closely related from small communities. Family trees go much wider than the go backwards. Everyone in terms of DNA may be related to everyone else BUT the DNA link between 3rd cousins is statistically small, between 4th and 5th cousins etc are statistically an insignificant % of DNA. Meaningful searches should be parental.

Groups where there were extremely close relatives, siblings and repetitive 1st cousin marriages do not prosper in health, longevity or reproduction. Inbreeding and incest results in a poor regeneration. Perhaps the most striking examples come from the great Pharaohs of Egypt and in dynasties who tightly retained succession (e.g. houses of Habsburg or Transamara). 1st cousin marriages were common across Europe until after the first world war.

Social groups in society have traditionally married within their class although there have always been spectacular Romeo and Juliet love stories as exceptions to the accepted class structures; fortune and fame have been oft lost for love.

ROYALTY- Kings, queens, princes and princesses.

UPPER NOBILITY - dukes, marquess, Earls, Counts.

LOWER NOBILITY- Barons, Lords, Ladies, Rt Hon, Much Hon, viscounts, meritocracy and non-hereditary lifetime peerages.

COMMONERS - and its sub social distinctions – working class, white collar, business, merchants, academia/intelligencia. In the most recent society we can add the CELEBRITY class who are famous for being famous by success (sport or the arts or science) or by media driven self-publication.

7. The higher the class the smaller the numbers. In times of war the upper classes made up the majority of leadership and were usually first in line and most often first over the top. Statistically the UPPER and LOWER NOBILITY were culled more effectively in military and colonial adventure by % of population group than say the enlisted or volunteer population. Consider that across Europe from the earliest times was at continuous war (colonial, succession, conquest, Napoleonic, 7-year, 100 year) before a final flourish of mass slaughter during two World Wars.

8. Famine and disease, great plagues, crop failures, forced emigration etc. Cholera, bubonic plague, smallpox and influenza are some of the most brutal killers in human history. Outbreaks of these diseases across international borders properly defined as pandemic, especially smallpox, which by itself throughout history, has killed between 300-500 million people in its 12,000-year existence.

How do we square up Chan’s trillion super grandparents with these undisputed critical factors in population growth?

The effect of each of these factors is significant and valid. Just a few examples change the statistics hugely.

War destroyed a large proportion of the population and decimated the nobility and aristocracy with regular precision.

Heinrich Hoffman, Frederick the Great. Published 2012.

A vital text of the rise of the changing patterns of war.

“..by the end of the Silesian war one-fifth of the population of Pomerania, 70,000 people, died of disease and privation between 1756 and 1763. In Neumark-Brandenburg, a quarter of the civilian population, almost 60,000 people, died or disappeared”.

“……….in 1763. Frederick the Great returned (from war) to a state shaken to its physical and moral foundations. Between 160,000 and 180,000 of his subjects had been killed in action or died of their wounds or disease. One noble family had lost twenty of its twenty-three males of military age”.

“…in Prussia in 1717 King Frederick William established a Corps of Cadets whose adolescent members were drawn from the ranks of the aristocracy”.

Like the ancient Athenian and Spartan civilizations armies were “born” to military service, a highly trained army generation on generation. Frederick also established a “giant army” of very tall soldiers, recruiting and resorting to press ganging.

The aristocracy were considered as leaders and upholders of the concept of state service an idea that continued for the following 200 years and well into the higher levels of military service in WW2.

Chan’s Trillion ancestors may provide the statisticians and social idealists with a masthead number but in reality, the numbers are much smaller. We are left now with a number that must account for the natural disasters, famine, disease, social condition and violence in society that prevailed across Europe and the considerable exposure of the nobility leading all others marching to their deaths.

We can look at the clues left by genealogists who use evidence to create family trees and ancestry. Written records can be found in abundance across Europe, births, deaths and marriages, property and legal conveyancing, written local parish and royal journals provide documentation that is critical to proving a line of descent. The digitisation of masses of records back up the archaeological evidence to make it much easier to track families and determine a more meaningful set of statistical possibilities.

How many can claim an ancestry as valid?

Keeping in mind the limiting factors (above) to Chan’s theory and setting aside the rule of primogeniture (descendance through the male line only) we should look at the those who hold a DIRECT parental line (no cousins) and those who can validate with documentation, records or births, deaths and marriages. Using circumstantial evidence is unreliable, (Queen Elizabeth 2nd would be displaced by an Australian Tudor descendant if credible circumstantial evidence were relied upon).

However, line of descent can be a good test of validity, royal documentation and graphic evidence is generally sound as far back as the year 700 AD.

In 2001, American genealogist William Addams Reitwiesner compiled a list of 4,973 living descendants of the Electress Sophia in order of succession, but did so disregarding Roman Catholic status. When updated in January 2011, the number was 5,753. This represents around 9 generations of monarchs and spreads across Europe and all corners of the world, through direct parentage, siblings, cousins and more than a few mistress offspring. So, it is 9 monarchs back and 5,753 documented ancestors wide. For simplicity “say” 6000.

So, what to deduct from each generation in Chan's theory. , say;

20% off for each generation with no children.

2. 15% off for birth mortality, mother or child (or both) up to WW1.

3. 10% for health failing in childhood.

4/5. 6% for cousin or close unions, (non commoners).

6. 10% for selecting social classifications (non commoners).

7. 10% for military exposure (non commoners) .

8. 25% for plagues local, regional and pandemics.

96% have gone. So we have a figure approximately 4% of where Chan started

Now, moderating Chan’s theory, 1 individual going back 10 generations back would have say 4% of 1,000 grand relatives, so 40 individuals x Reitweisner’s 6000 = 240,000 direct relatives across EUROPE.

This 4% can be compared against the American Museum of Natural History population model which had the EUROPEAN population reaching 35 million just after the year 1400 then falling back during the great plagues (the only time the world population has declined) then by 1700 and the Sophie Succession reaching 60 million, (8 generations ago in the Low ancestry). 4% of 60 million is 240,000.

FOR INFORMATION

From 1700 to 1800 the WORLD population had risen to 1 billion, by 1900 1.6 billion World population is estimated to be 6.5 billion by 2020.

In 2011 Europe was 11% (and falling) of the world population so a fair estimate of the European population in 2020 would be 10% of 6.5 billion, so 650 million.

The world now has a combined population of almost 8 billion.

India and China now have a total population of 2.8 billion.

The top 10 countries of the world (including China and India) have 4.5 billion people.

Europe has around 650 million people.

The UK has around 66 million people.

AND FINALLY.

Tracing population will one day be at the touch of a key as more and more records are digitalised and networked. But there remain many records that are a blank. Europe is exceptionally rich in family, local and national records and evidential artefacts. Most of the best records prior to 1700 lie within named family ancestral documentation. DNA now forms part of the evidence in verifying people history.

We remain all linked by traces of DNA. How statistically significant that % will be discussed and argued about as long as the subject is researched. Like Homeopathic medication the presence of any particular essence will never be in doubt, there will always be a trace no matter how many times it is diluted. However, the value in such a distant and almost unmeasurable quantity whilst at molecular level it may have an influence, it will not reflect who we are or were.

Ole J. Benedictow calculated that the Black Death killed 50 million people in the 14th century, or 60 per cent of Europe’s entire population. 3 generations were wiped out.