A significant development in J-L283 research has occurred with the last YFull update (v8.00.00).
Before the update this clade was a bottleneck starting 7700 BC and ending 3400 BC. While it is possible to estimate where the ancestor at the beginning and end of a bottleneck had been living based on upstream and downstream diversity, there is no genetic evidence pointing to where they were living in between.
The oldest J-L283 ancient sample was from the North Caucasus (Kabardino-Balkaria), but only dated to 1900 BC, it isn't old enough to conclude where the J-L283 common ancestor had been living in 3400 BC. But since this sample was negative for many of the important earliest mutations it hinted that the ancestors were living near the Caucasus.
Armenian Splits J-L283 4100 BC
A small window into the ancient origins of J-L283 opened up with the discovery that an Armenian man tracing descent to Harpoot tested positive for most J-L283 SNPs but negative for several.
In 4100 BC, the J-L283 most recent common ancestor had two sons. One son went on to become the Armenian from Harpoot. The other son sired a succession of men that for the next 700 years formed a bottleneck, now known as J-Z622, the living descendants of which trace descent to Europe.
If the modern Armenian J-L283* and the ancient samples from North and South Caucasus are circumstantial evidence that our J-L283 ancestors had been living in the Caucasus, then the 700 year J-Z622 bottleneck represents a migration from the Caucasus to Europe.
To put this in an archaeological context, the most recent common ancestor of J-L283 lived at the same time that agriculture was introduced to the South Caucasus and Armenian Highlands, through a culture known as Shulaveri-Shomu. I do not know how to find more reliable information on this culture but the wikipedia article suggests a range of 4000-2000 BC.
"Many of the characteristic traits of the Shulaverian material culture (circular mudbrick architecture, pottery decorated by plastic design, anthropomorphic female figurines, obsidian industry with an emphasis on production of long prismatic blades) are believed to have their origin in the Near Eastern Neolithic (Hassuna, Halaf)." - Shulaveri Shomu article from Wikipedia
So there are links between the Shulaveri Shomu culture and the Near East Neolithic. I think it doesn't make sense to go into more detail here until additional living or older ancient J-L283 samples from the Caucasus / Near East join the YFull tree so we can get a better idea on geographical and time constraints.
J-Z622 Bottleneck : Possible Migration to Europe from 4100-3400 BC
The migration to Europe - again this is assuming a non-European origin of J-L283 which is just based on circumstantial evidence now - took a maximum of 700 years. We are actually very lucky to have such a precise range based on genetic evidence. The migration could have started anytime after 4100 BC and ended anytime before 3400 BC.
The Yamnaya are considered the most likely vector of the Ancestral North Eurasian autosomal component in modern Europeans. They contributed heavily genetically and culturally to the Corded Ware culture, one of the Final Neolithic cultures.
"Lazaridis et al. (2016) proposes a different people, likely from Iran, as the source for the Middle Eastern ancestry of the Yamnaya people, finding that "a population related to the people of the Iran Chalcolithic contributed ~43% of the ancestry of early Bronze Age populations of the steppe". - The Genetic Structure of the World's First Farmers
A connection to the Yamnaya or related groups around 3400 BC appears possible, though at this point based only on rough circumstantial evidence such as the above, on approximate dates and the fact that a J-L283 was found in the North Caucasus from 1900 BC. We will need to wait for more ancient and modern samples to get a clearer picture of how our ancestors entered Europe.
While J-Z600 diversified immediately in 3400 BC primarily around the Mediterranean but also siring two J-Z615* lineages from Germany and England, J-YP91 underwent a bottleneck until 2000 BC.
For all of our ancestors before the explosion of J-Z2507 in the Balkans 2400 BC, it was relatively hard times. We have relatively few survivors of these lineages. Sardinia and the Caucasus are known as genetic refugia because lineages which get replaced in more attractive or easy to reach areas are able to survive in relative geographic isolation. When invaders do enter they can escape by going into the mountains where they are less likely to be pursued.
The recent discovery of ancient NW European diversity within J-YP91 showed we were justified to regard Sardinia as a refuge of J-L283 lineages, rather than an origin of J-L283 itself. The ancient J-L283 from Sardinia points to one lineage of J-L283 having migrated there by 1200 BC, in line with a Bell Beaker mediated migration from Italy.
I've recently identified a Polish cluster of distantly related men who may be J-YP91. One of them plans to do NGS/WGS so hopefully we will learn more in the near future.
More likely than not, many of the answers we seek are already present in the DNA of J-M241 project members. We can make great strides in research by educating our members and showing them how fascinating the story of our ancestors is.
Anyone can become a haplogroup researcher and further this goal by encouraging their matches to test.