Exhibit 99.1

CUSIP No. 05454B105

JOINT FILING AGREEMENT

The persons below hereby agree that the Schedule 13D to which this agreement is attached as an exhibit, as well as all future amendments to such Schedule 13D, shall be filed jointly on behalf of each of them. This agreement is intended to satisfy the requirements of Rule 13d-1(k)(1)(iii) under the Securities Exchange Act of 1934.

Dated: May 20, 2020

FLAGSHIP VENTURELABS IV, LLC
By:	Flagship Ventures Fund IV, L.P.
By:	Flagship Ventures Fund IV General Partner LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES FUND IV, L.P.
By:	Flagship Ventures Fund IV General Partner LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES FUND IV-Rx, L.P.
By:	Flagship Ventures Fund IV General Partner LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES FUND IV GENERAL PARTNER LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES FUND 2007, L.P.
By:	Flagship Ventures 2007 General Partner LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES 2007 GENERAL PARTNER LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES OPPORTUNITIES FUND I, L.P.
By:	Flagship Ventures Opportunities Fund I General Partner LLC

CUSIP No. 05454B105

By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
FLAGSHIP VENTURES OPPORTUNITIES FUND I GENERAL PARTNER LLC
By:	/s/ Noubar B. Afeyan, Ph.D.
Name:	Noubar B. Afeyan, Ph.D.
Title:	Manager
/s/ Noubar B. Afeyan, Ph.D.
NOUBAR B. AFEYAN, PH.D.