So from the new data dump I went looking for my mtdna, which is pretty rare. Of the 10,000 samples, only 37 were u1a1a, of those 37 only 22 had Y calls also.
This haplo has a 9000TMRCA acc to Yfull, so I don't know if we can reliably extrapolate anything, however there were potentially some interesting results.
Of the 22 with Y calls, 12 of them fell under R-M173, which is more than half. Two of those are R1b-Z2103, one is R1b-P7562, one is R1a, with the rest being downstream of R-L151.
For the rest, one is E-V13, two are I-M170, four are under G-L1259, two are under T-Z19859, and one is under L-595
From this small sample set, it is still speculative, but it seems to potentially suggest that U1a1a has some sort of centre of gravity in the direction of R-M173.
| E-BY4280 | E-BY4280 | E-M96>CTS9083>P147>P177>P2>M215>M35>V68>M78>PF2179>Z1919>L618>CTS1975>V13>CTS8814>CTS5856>BY4877>BY3880>Z5017>Z5016>SK888>CTS6377>CTS2001>CTS9320>Z17264>BY4280 | ... | U1a1a1 |
| G-FTH126 | G-FTH126 | G-M201>L89>L156>P15>L1259>L30>L141>P303>L140>PF3346>Z3065>PF3345>FTB86>FTH126 | ... | U1a1a+16129 |
| G-Z1817 | G-Z1817 | G-M201>L89>L156>P15>L1259>L30>L141>P303>L140>PF3346>Z3065>PF3345>L497>CTS9737>Z1900>Z6901>Z1817 | ... | U1a1a |
| G-Z30814 | G-Z30814 | G-M201>L89>L156>P15>L1259>L30>M406>PF3299>PF3293>PF3296>Z30814 | ... | U1a1a3 |
| G-Z42732 | G-Z42732 | G-M201>L89>L156>P15>L1259>PF3146>PF3148>PF3177>FGC2263>L91>S19852>Z42562>Z42732 | ... | U1a1a |
| I-S10702 | I-S10702 | I-L758>M170>P215>CTS2257>L460>P214>M223>P222>CTS616>CTS10057>L702>P78>S9302>S25733>A427>S23897>S23612>S10702 | score_tie;most_recent_common_parent | U1a1a |
| I-Z2041 | I-Z2041 | I-L758>M170>Z2699>L840>M253>DF29>Z58>Z59>Z2041 | ... | U1a1a |
| L-L595 | L-L595 | L-M20>L595 | ... | U1a1a1 |
| R-P312 | R-P312 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312 | step_rule | U1a1a |
| R-P312 | R-P312 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312 | score_tie;most_recent_common_parent | U1a1a |
| R-BY28613 | R-BY28613 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z290>L21>S552>DF63>CTS6919>A92>Z16506>FGC17164>A7804>BY28613 | step_rule | U1a1a |
| R-Y32775 | R-Y32775 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z46516>ZZ11>U152>L2>Z49>Z142>FT32075>CTS2819>Y32775 | ... | U1a1a |
| R-CTS11874 | R-CTS11874 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z46516>ZZ11>U152>PF6658>Z192>PF6652>FT354146>CTS11874 | ... | U1a1a |
| R-Y185723 | R-Y185723 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z46516>ZZ11>U152>Z36>CTS5531>Z54>CTS1595>FT398695>Y185723 | ... | U1a1a |
| R-FTB46484 | R-FTB46484 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z46516>ZZ11>U152>Z36>Y17161>BY1328>BY2151>A7992>FGC59783>FGC71023>FTB46484 | ... | U1a1a |
| R-CTS12976 | R-CTS12976 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>L51>P310>L151>P312>Z46516>ZZ11>U152>Z56>BY3548>Z43>Z46>Z48>CTS12976 | ... | U1a1a |
| R-FTA13338 | R-FTA13338 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>Z2103>M12149>Y13369>L584>PF7580>FTA70761>Y19434>A12332>FT31418>FTA59273>FTA13338 | ... | U1a1a+16129 |
| R-BY205820 | R-BY205820 | R-M207>M173>M343>L754>L761>L389>P297>M269>L23>Z2103>M12149>Y4362>Y4364>Y84551>FT18731>FT310230>FT307174>BY205820 | ... | U1a1a |
| R-PF7562 | R-PF7562 | R-M207>M173>M343>L754>L761>L389>P297>M269>PF7562 | ... | U1a1a |
| R-FT135115 | R-FT135115 | R-M207>M173>M420>M459>CTS5437>M515>M198>M417>PF6162>Z283>Z282>Z280>CTS1211>Y35>CTS3402>Y2613>Y2617>Y2615>Y40718>FT135115 | ... | U1a1a |
| T-BY28259 | T-BY28259 | T-M184>L490>M70>Z19859>L131>Z19935>L446>Y6055>CTS933>CTS10803>FT127659>Z19890>Y21204>BY28259 | ... | U1a1a |
| T-Z711 | T-Z711 | T-M184>L490>M70>Z19859>L454>L208>CTS931>CTS11451>Y4119>CTS2214>BY28451>Z709>CTS7703>CTS8512>L906>CTS8603>CTS6174>P77>CTS2860>Z711 | ... | U1a1a |
