Sudanese Nile Valley Population stable for 10,000 Years

The research indicated that their was no population replacement from Mesolithic to Christian period in the Nile Valley. The authors wrote: “While evidence from the archaeology and mortuary archaeology discussed in the
Introduction does not demonstrate any population replacements from the Mesolithic and on, Nubian history is punctuated by extensive contact with other peoples, including the Romans and Egyptians (c.f., Krings et al. 1999; Smith 1998), which might explain the maintenance of similar
levels of extraregional gene flow over time from our first hypothesis.” 


In the conclusion the authors noted that: "In this paper, the population structure of Nubians, as constructed from the skeletal record, was examined in relation to the environmental, archaeological, and mortuary evidence in order to interpret population genetics parameters in conjunction with the historic record. It was discovered that the samples mostly clustered by site, which in combination with the
archaeological evidence of social isolation operating on some samples, balanced with their biological similarity to other samples that display evidence of extensive contact with different peoples, suggest that extraregional gene flow was probably punctuated with genetic drift, at least in three of the samples we examined. Our results also discount a population replacement happening during the range of time examined in this study. " 

In summary the Nile Valley people even though they have interacted with non-Africans from millenia, they have remained Black . You can read Evaluating Nubian Population Structure from Cranial Nonmetric Traits: Gene Flow, Genetic Drift, and Population History of the Nubian Nile Valley. See:  Evaluating Nubian Population Structure from Cranial Nonmetric Traits: Gene Flow, Genetic Drift, and Population History of the Nubian Nile Valley