X0306 4 2021-02-08 0 0001770121 Sana Biotechnology, Inc. SANA 0001757011 ARCH Venture Fund X, L.P. 8755 WEST HIGGINS ROAD SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001219039 CRANDELL KEITH 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001219043 BYBEE CLINTON 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001569248 Burow Kristina 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 0001229592 GILLIS STEVEN 8755 WEST HIGGINS ROAD, SUITE 1025 CHICAGO IL 60631 0 0 1 0 Common Stock 2021-02-08 4 C 0 10156250 A 10303750 I See Footnotes Common Stock 2021-02-08 4 C 0 10156250 A 10301250 I See Footnotes Common Stock 2021-02-08 4 C 0 11718750 A 11718750 I See Footnotes Common Stock 2021-02-08 4 C 0 11718750 A 11718750 I See Footnotes Series A-1 Convertible Preferred Stock 2021-02-08 4 C 0 3687500 0.00 D Common Stock 3687500 0 I See Footnotes Series A-1 Convertible Preferred Stock 2021-02-08 4 C 0 3687500 0.00 D Common Stock 3687500 0 I See Footnotes Series A-2 Convertible Preferred Stock 2021-02-08 4 C 0 5687500 0.00 D Common Stock 5687500 0 I See Footnotes Series A-2 Convertible Preferred Stock 2021-02-08 4 C 0 9375000 0.00 D Common Stock 9375000 0 I See Footnotes Series A-2 Convertible Preferred Stock 2021-02-08 4 C 0 9375000 0.00 D Common Stock 9375000 0 I See Footnotes Series A-2 Convertible Preferred Stock 2021-02-08 4 C 0 5687500 0.00 D Common Stock 5687500 0 I See Footnotes Series B Convertible Preferred Stock 2021-02-08 4 C 0 781250 0.00 D Common Stock 781250 0 I See Footnotes Series B Convertible Preferred Stock 2021-02-08 4 C 0 781250 0.00 D Common Stock 781250 0 I See Footnotes Series B Convertible Preferred Stock 2021-02-08 4 C 0 2343750 0.00 D Common Stock 2343750 0 I See Footnotes Series B Convertible Preferred Stock 2021-02-08 4 C 0 2343750 0.00 D Common Stock 2343750 0 I See Footnotes The shares of Issuer's Preferred Stock automatically converted into shares of Issuer's Common Stock, for no additional consideration, on a 1-for-1 basis immediately prior to the consummation of Issuer's initial public offering. Represents shares held directly by ARCH Venture Fund IX, L.P. (ARCH IX). ARCH Venture Partners IX, L.P. (AVP IX LP) is the sole general partner of ARCH IX. Represents shares held directly by ARCH Venture Fund IX Overage, L.P. (ARCH IX Overage). ARCH Venture Partners IX Overage, L.P. (AVP IX Overage LP) is the sole general partner of ARCH IX Overage. ARCH Venture Partners IX, LLC (AVP IX LLC) is the sole general partner of each of AVP IX LP and AVP IX Overage LP. Keith Crandell and Clinton Bybee are managing directors of AVP IX LLC (the AVP IX MDs). AVP IX LP and AVP IX Overage LP may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, respectively, AVP IX LLC may be deemed to beneficially own the shares held by ARCH IX and ARCH IX Overage, and each of the AVP IX MDs may be deemed to share the power to direct the disposition and vote of the shares held by ARCH IX and ARCH IX Overage. AVP IX LP, AVP IX Overage LP, AVP IX LLC, and the AVP IX MDs each disclaim beneficial ownership except to to the extent of any pecuniary interest therein. Represents shares held directly by ARCH Venture Fund X, L.P. (ARCH X). ARCH Venture Partners X, L.P. (AVP X LP) is the sole general partner of ARCH X. Represents shares held directly by ARCH Venture Fund X Overage, L.P. (ARCH X Overage). ARCH Venture Partners X Overage, L.P. (AVP X Overage LP) is the sole general partner of ARCH X Overage. ARCH Venture Partners X, LLC (AVP X LLC) is the sole general partner of each of AVP X LP and AVP X Overage LP. Keith Crandell, Kristina Burow and Steven Gillis are members of the investment committee of AVP X LLC (the AVP X Committee Members). AVP X LP and AVP X Overage LP may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, respectively, AVP X LLC may be deemed to beneficially own the shares held by ARCH X and ARCH X Overage, and each of the AVP X Committee Members may be deemed to share the power to direct the disposition and vote of the shares held by ARCH X and ARCH X Overage. AVP X LP, AVP X Overage LP, AVP X LLC, and the AVP X Committee Members each disclaim beneficial ownership except to the extent of any pecuniary interest therein. The expiration date is not relevant to the conversion of these securities. Form 2 of 2. /s/ Keith Crandell, By: Mark McDonnell, attorney in-fact 2021-02-10 /s/ Clinton Bybee, By: Mark McDonnell, attorney in-fact 2021-02-10 /s/ Kristina Burow, By: Mark McDonnell, attorney in-fact 2021-02-10 /s/ Steven Gillis, By: Mark McDonnell, attorney in-fact 2021-02-10