Flagship Ventures Fund V SC 13D/A Kaleido Biosciences / Flagship Ventures Fund V ownership change

Exhibit 1

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: February 10, 2021	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 GENERAL PARTNER LLC
		By:	/s/ Noubar B. Afeyan, Ph.D.
		Name:	Noubar B. Afeyan, Ph.D.
		Title:	Manager
	FLAGSHIP VENTURELABS V, LLC
	By:	Flagship VentureLabs V Manager LLC
	By:	Flagship Pioneering, Inc.
		By:	/s/ Noubar B. Afeyan, Ph.D.
		Name:	Noubar B. Afeyan, Ph.D.
		Title:	Director
	FLAGSHIP VENTURELABS V MANAGER LLC
	By:	Flagship Pioneering, Inc.
		By:	/s/ Noubar B. Afeyan, Ph.D.
		Name:	Noubar B. Afeyan, Ph.D.
		Title:	Director

FLAGSHIP PIONEERING, INC.
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Director
FLAGSHIP VENTURES FUND V, L.P.
By:	Flagship Ventures Fund V General Partner LLC
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Manager
NUTRITIONAL HEALTH SIDE FUND, L.P.
By:	Flagship Ventures Fund V General Partner LLC
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Manager
NUTRITIONAL HEALTH DISRUPTIVE INNOVATION FUND, L.P.
By:	Flagship Ventures Fund V General Partner LLC
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Manager
FLAGSHIP VENTURES FUND V GENERAL PARTNER LLC
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Manager
NUTRITIONAL HEALTH LTP FUND, L.P.
By:	Nutritional Health LTP Fund General Partner LLC
	By:	/s/ Noubar B. Afeyan, Ph.D.
	Name:	Noubar B. Afeyan, Ph.D.
	Title:	Manager

NUTRITIONAL HEALTH LTP FUND 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
	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
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
CADENA 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.