EHGs in turn derived 75% of their ancestry from ANEs. Scandinavian Hunter-Gatherers (SHGs) were found to be a mix of EHGs and WHGs. A 2017 genetic study published in "Current Biology" in February 2017 determined that the people of the Mesolithic Kunda culture and the Narva culture of the eastern Baltic were a mix of WHG and EHG, showing the closest affinity with WHG. Samples from the Ukrainian Mesolithic and Neolithic were found to cluster tightly together between WHG and EHG, suggesting genetic continuity in the Dnieper Rapids for a period of 4,000 years. The Ukrainian samples belonged exclusively to the maternal haplogroup U, which is found in around 80% of all European hunter-gatherer samples. A genetic study published in "Current Biology" in July 2017 found that people of the Pit–Comb Ware culture (CCC) of the eastern Baltic were closely related to EHG, unlike earlier hunter-gatherers in the area, who were more closely related to WHG. A genetic study published in "PLOS Biology" in January 2018 analyzed 13 SHGs and found all of them to be of WHG ancestry. SHGs from western and northern Scandinavia had less WHG ancestry (ca 51%) than individuals from eastern Scandinavia (ca. 62%). The authors of the study suggested that the SHGs were a mix of WHGs who had migrated into Scandinavia from the south, and EHGs who had later migrated into Scandinavia from the northeast along the Norwegian coast. The WHGs who entered Scandinavia are believed to have belonged to the Ahrensburg culture. EHGs and WHGs displayed lower allele frequencies of SLC45A2 and SLC24A5, which cause depigmentation, and OCA/Herc2, which causes light eye color, than SHGs. In a genetic study published in "Nature Communications" in January 2018 found that members of the Kunda culture and Narva culture were closely related with WHG, while the Pit–Comb Ware culture was more closely related to EHG. Southern areas of the eastern Baltic were found to be more closely related to WHG than northern and eastern areas. Unlike most WHGs, the WHGs of the eastern Baltic did not receive European farmer admixture during the Neolithic. Modern populations of the eastern Baltic thus harbors a larger amount of WHG ancestry than any other population in Europe. A study published in "Nature" in February 2018 included an analysis of a large number of individuals of prehistoric Europe.