That is false, it dates back to the medieval Kingdom of Bosnia. Read the book "Bosnia: a Short History" by Noel Malcolm, and read the writings of friar
Antun Knežević.
It is already known what we are, we are more European than both Serbs and Croats. Serbs have more neolithic Near-Eastern ancestry, Croats have more Bronze Age Indo-European ancestry from Central Asia.
http://www.eupedia.com/europe/european_y-dna_haplogroups.shtml
Let’s talk about the facts. Serbs are typical Balkan population. You can see MDS scaling in many scientific papers.
You can see difference between Bosniacs and Serbs in Serbia (for Bosnian Serbs is small sample).
I1 is twice higher in Serbia (Serbs 8,5, Bosniacs 4)
I2a is for 2/3 higher in Bosniacs (Serbs 33, Bosniacs 56)
R1a is same (Serbs 16%, Bosniacs 16%)
R1b is much higher in Serbs (Serbs 8%, Bosniacs 3%)
J2 is twice higher in Serbs (Serbs 8%, Bosniacs 3,5%)
E1b1b1a2 is higher in Serbs (Serbs 18%, Bosniacs 10%).
We can compare with any east European nation, for example Belarus, who is closer to them Bosniacs or Serbs.
Bosniacs have much more I2a and Belarus have much more R1a. But we can see the sum I2a+R1a, scientists often relate these two haplogroups.
Bosniacs have 72%, and Belarus have 68,5%.
But Serbs have less than 50%, accurate 49%. You can see for other Balkan nations, Romanians have 45,5%, Macedonians* (Noveski et al.) 41,7%, Montenegrins 37%, Bulgarians 37%, Tosk Albanians about 29%, Greeks 25%.
*Macedonians from former Yugoslav republic, not Aegean Macedonians in Greece
You can see for J2. Bosniacs have 3,5% and Belarus have 2,5%.
Serbs have 8%, Montenegrins 9%, Macedonians 10% (Noveski et al.), Bulgarians 11%, Romanians 13,5%, Tosk Albanians 23%, Greeks 23%.
You can see for R1b, E1b1b1a2 etc. Bosniacs and Belarus are much different compared to Serbs, Montenegrins, Macedonians, Romanians, Bulgarians, Tosk Albanians or Greeks.
And who are closer to east Europeans and who are closer to other Balkan peoples?
Conclusion is that Serbs are similar to other Balkan peoples and Bosnicas are closer to east European peoples.
But Bosniacs are closer to other Balkan peoples compared to Croats in mainland (Croatia). Also Bosniacs are closer other Balkan peoples compared to Geg Albanians.
Bosniacs are very specific for Balkans, they are untypical, due to the very high I2a and much lower R1b, E1b1b1a2, J2 etc. compared with other Balkan peoples.