Notes on the Map of DNA samples in East Anglia, both compiled by Stephen Arbon. 1. Objectives of the MapTo see if there were any significant patterns of the main haplogroups of DNA of project members and any correlation between them and geographical, historical or man-made features in East Anglia.2. Study Area of East AngliaEast Anglia for the project includes:
At one time the region was smaller, with the boundaries defined by several more defendable geographical features:
3. Observations of Results
• for ‘R1b’ haplogroup
• for ‘I’ haplogroup
4. Preparation of the Information4.1 The Plotting of Dna Samples on the MapThe location & haplogroup of the samples was copied from information listed on the spreadsheet from the East Anglia Project web-site [15 Feb 2009], and is based on what was provided by project participants, giving the baptism or birth [parish] of their earliest known male ancestor.These locations were then plotted on a scanned copy of an AA 1:250 000 map. 4.2 Roads & TownsOnly the principal roads & towns, as they were in about 1830, are shown on the map .These were copied from ‘A New and Comprehensive Gazetteer of England and Wales of 1834’ by James Bell, as printed in ‘Phillimores ATLAS and INDEX of Parish Registers’. [Although there’s a large network of local roads, paths & villages that haven’t been included]. The positions of markers should be close but may not be exact because:
4.3 Rivers & Waterways[yet to be completed] 5. Many Areas are Still Largely Under Represented- Several populated areas which lie along the periphery of East Anglia, eg Cambridge & Colchester. - Other areas may have only ever supported thin populations such as:
- Some locations have no obvious reason for a lack of samples, eg Thetford, Claire, Haverhill etc. and may be just thru chance. 6. Sample Size and ProbabilityThe number of dna markers so far submitted to the project only represent a tiny proportion of the population of East Anglia, ie a couple of hundred out of perhaps a half a million in the early 19th century. In addition, they are not a random sample. While this might not effect the accuracy of the overall results it certainly would if looking at any of the less populated areas. 6.1 Sample Size to PopulationThe sampling size needed for an accurate prediction of a population is related to the diversity in the parent population [ie the standard deviation], not its total size. Additionally, the minimum total sample size is recommended to be at least 50 points for statistical correctness, for a normal distribution of a population.So in our case, the 140 participants would seem to give a reasonably size for Norfolk & Suffolk taken as a whole and assuming they was no inherent bias from the way they were supplied that might skew the results]. 6.2 Randomness of the SamplesThere are a number of factors that mean that the project samples aren’t truly random: - Internal Movement & Migration While the movement of people before the Tuder period is largely unknown, in later times, rural workers often moved in May within their ‘hundred’ depending on work on offer. Additionally there was a large drift out of Suffolk & Norfolk in the 18th & 19th centuries to other regions such as Yorkshire & London and to other countries such as Australia, Canada, & New Zealand. As well as the earlier movements of the religious non-conformers to the American colonies in the 16th-18th centuries. If for instance, farm workers were more likely to have been descended from the Angles for instance, and they were the ones who migrated, than the results may be skewed in a particular way. - Wealth Those with spare finance [eg America] would be more likely to have had dna tests. - Possible Effects of having the same Co-ordinator As David Weston has been significant part of both East Anglia dna & an U106 dna projects, there may be a higher representation from that clad. 6.3 Effects of ChanceBased on the dna results sampled so far, one might expect for every 10 samples for a parish there should be:
7. Geographical Factors7.1 WaterwaysThe river systems dominate the pattern of settlement in East Anglia, although in slightly varying ways to what would be the case in other regions:
7.2 Road Network and Towns[yet to be completed] |
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Arbon Map (2013.09)
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