MOESAN
Elite member
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- Brittany
- Ethnic group
- more celtic
- Y-DNA haplogroup
- R1b - L21/S145*
- mtDNA haplogroup
- H3c
hello
sorry for my curious english
here some thinkings about the matter:
1st post to Eupedia
The problem of number and density in the ancient populations : it should have some impact on the interpretations we can do about the possible bottlenecks and founder effects, and also on the mobility of these populations and the impact of genetic admixtures. What I believe is that the more the period is close to our time the more the Europe people was numerous and the minder all these accidental phenomenons are likely to have taken place. What should be very interesting should to have good datas about the Europe population through the ages. Archeolology is of great worth in helping to measure the density of human populations even if the different quality of soils and reliefs can be obstacles to the understanding of reality. When a read very often there was nobody out of the southern refuges I the Last Glacial Maximum I am not so convinced. Archeology shows that there was some people in the northern central Europe in the middle of these ages even if the density was inferior to the one of the refuge regions. When I think to the very different phenotypes (metrical and others) found in Europe I can not imagine they could be caused by big repopulating movements. I am aware of the contempt about traditional physical anthropology. By the way phenotypes are caused by genotypes (with some distortions) and the human beings was fewer and fewer under natural selection. The external phenotypes are maybe fewer under selection than other autosomals like those of the blood. I am obliged to imagine several little zones inhabited by a few peoples and isolated each from the other. It is not only a matter of time for selecting genes but above all a matter of needed isolation for the process of selection on a necessary little enough number of men: phenotypes can not be so new in despite of some claims, I believe. Consequence: it is very possible that some of the core of present days numerous enough marginal populations was at the beginning small populations whose demography knew a big boom: not at one time only but at several periods, not the same for all peoples. A metric type (based on serious studies and a lot of scientific considerations) can not find place without these conditions. There is no need to say that after these periods of isolating these populations were less or more submitted to crossings, light or heavy according to every history. The problem stays there: isolating and growing up, but where and when?
All these aspects have their weight because a maintained small level of population can lead to two contrary results (“law of the small numbers”?): a old SNP based HG without new branches even if far from its origin place OR a new HG staying yet in “native” place its anceytors. It does not happen every time but it can occur sometimes. The STRs are of no use in the case of very different HGs based on SNPs. They just can tell us something on age when they are diverse AND star like, knowingthat some back migrations can send back other STRs. The Caucasus shows very near (geographically & in regard of autosomals) populations, isolated by relief even more than by culture, and with very different, often opposite in distributions of HG-Y (almost not coding), even when sharing the same culture! So isolation (passed and present) by relief or distance can bias the timing of the story and the scenario and it is very important to do with other ways of approach like binary alleles, metrics and non metric physical studies (reflecting incompletely work of binary alleles) and demographic studies when possible. It is sure the weight of isolation and deriving became lighter and lighter as time passed.
sorry for my curious english
here some thinkings about the matter:
1st post to Eupedia
The problem of number and density in the ancient populations : it should have some impact on the interpretations we can do about the possible bottlenecks and founder effects, and also on the mobility of these populations and the impact of genetic admixtures. What I believe is that the more the period is close to our time the more the Europe people was numerous and the minder all these accidental phenomenons are likely to have taken place. What should be very interesting should to have good datas about the Europe population through the ages. Archeolology is of great worth in helping to measure the density of human populations even if the different quality of soils and reliefs can be obstacles to the understanding of reality. When a read very often there was nobody out of the southern refuges I the Last Glacial Maximum I am not so convinced. Archeology shows that there was some people in the northern central Europe in the middle of these ages even if the density was inferior to the one of the refuge regions. When I think to the very different phenotypes (metrical and others) found in Europe I can not imagine they could be caused by big repopulating movements. I am aware of the contempt about traditional physical anthropology. By the way phenotypes are caused by genotypes (with some distortions) and the human beings was fewer and fewer under natural selection. The external phenotypes are maybe fewer under selection than other autosomals like those of the blood. I am obliged to imagine several little zones inhabited by a few peoples and isolated each from the other. It is not only a matter of time for selecting genes but above all a matter of needed isolation for the process of selection on a necessary little enough number of men: phenotypes can not be so new in despite of some claims, I believe. Consequence: it is very possible that some of the core of present days numerous enough marginal populations was at the beginning small populations whose demography knew a big boom: not at one time only but at several periods, not the same for all peoples. A metric type (based on serious studies and a lot of scientific considerations) can not find place without these conditions. There is no need to say that after these periods of isolating these populations were less or more submitted to crossings, light or heavy according to every history. The problem stays there: isolating and growing up, but where and when?
All these aspects have their weight because a maintained small level of population can lead to two contrary results (“law of the small numbers”?): a old SNP based HG without new branches even if far from its origin place OR a new HG staying yet in “native” place its anceytors. It does not happen every time but it can occur sometimes. The STRs are of no use in the case of very different HGs based on SNPs. They just can tell us something on age when they are diverse AND star like, knowingthat some back migrations can send back other STRs. The Caucasus shows very near (geographically & in regard of autosomals) populations, isolated by relief even more than by culture, and with very different, often opposite in distributions of HG-Y (almost not coding), even when sharing the same culture! So isolation (passed and present) by relief or distance can bias the timing of the story and the scenario and it is very important to do with other ways of approach like binary alleles, metrics and non metric physical studies (reflecting incompletely work of binary alleles) and demographic studies when possible. It is sure the weight of isolation and deriving became lighter and lighter as time passed.