Born in marriages between distant relatives more children

Marriages between second cousins and siblings are chetveroyurodnymi with much more than marriages between people, took place in the more distant relatives. This is the result of the participants of the research project DeCODE reached, the genealogical records inhabitants of Iceland, studied in the last 200 years. According to scientists, the Icelandic women were 1800 to 1824 years and was married to a cousin of the second degree, was born, were born with an average of 4.04 children and 9.17 grandchildren. Contemporaries is married to more distant relatives (8 degrees and above), had an average of 3.34 children and 7.31 grandchildren. The observed trend continued throughout the period covered by the researchers. So, for women born from 1925 to 1949, these figures had 3.27 children and 6.64 grandchildren marry second cousins and 2.45 children and 4.86 grandchildren marriages with distant relatives or are not in the ratio of men. Created statistically significant effect of the degree of relationship to the number of children in families siblings chetveroyurodnymi found. Cousins - but the increase was not seen so many children in marriages between cousins. Related to increased fertility of couples from distant, often mentioned, confirm the study's authors. But until recently it was unclear whether this feature is a result of biological and socio-cultural characteristics of the human population. Since ethnicity in the entire period studied Icelandic population remained and culturally homogeneous, can be seriously maintained that the causes of many couples biological children, they say. It is known that marriage between close relatives (cousins and brothers and sisters), the probability of mutation and inheritance of offspring to increase severe genetic diseases. At the same time, marriages between more distant relatives may have a distinct advantage. For example, hereditary immune system reduced because of the similarity of the parents the likelihood of an immune response conflict between mother and fetus, the. Often the cause of miscarriage in early pregnancy