6. Property and Equipment, Net

At December 31, 2021 and 2020, property and equipment, net were comprised of the following (in thousands):

Property and equipment at December 31, 2021 and December 31, 2020 includes $79,000 in financing leases. In September 2020, Lineage terminated its leases in Alameda and entered into a new lease for a reduced amount of square footage. This resulted in a reduction to right-of-use assets of approximately $1.4 million. See additional information in Note 14.

Depreciation and amortization expense amounted to $663,000 and $823,000 for the years ended December 31, 2021 and 2020, respectively. During the year ended December 31, 2021, Lineage sold non-capitalized assets for a net gain of $30,000, which was included in R&D expenses on the consolidated statements of operations. During the year ended December 31, 2021, Lineage sold equipment with a net book value of $9,000 and recognized a gain of $5,000. Additionally, Lineage wrote off assets with a net book value of $29,000.

During the year ended December 31, 2020, Lineage sold equipment with a net book value of $32,000 and recognized a loss of $9,000. Lineage also wrote off assets with a net book value of $156,000, with $104,000 of this amount related to the termination of its leases in Alameda. Additionally, Lineage sold non-capitalized assets for a net gain of $72,000.