The gross carrying amounts and accumulated amortization of other intangible assets by major class are as follows:



	March 31, 2012							December 31, 2011
	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
Intangible assets subject to amortization (Definite-lived):
Customer lists	$	1,859	$	(248	)	$	1,611	$	1,841	$	(220	)	$	1,621
Patents	514		(84		)	430		518		(77		)	441
Purchased and licensed technology	1,920		(934		)	986		1,854		(878		)	976
Trademarks	57		(26		)	31		57		(25		)	32
Other ¹	326		(149		)	177		330		(151		)	179
	4,676		(1,441		)	3,235		4,600		(1,351		)	3,249

Intangible assets not subject to amortization(Indefinite-lived):
In-process research and development	70		—			70		70		—			70
Microbial cell factories ²	306		—			306		306		—			306
Pioneer germplasm ³	975		—			975		975		—			975
Trademarks/tradenames	824		—			824		813		—			813
	2,175		—			2,175		2,164		—			2,164
Total	$	6,851	$	(1,441	)	$	5,410	$	6,764	$	(1,351	)	$	5,413


¹	Primarily consists of sales and grower networks, marketing and manufacturing alliances and noncompetition agreements.

Microbial cell factories, derived from natural microbes, are used to sustainably produce enzymes, peptides and chemicals using natural metabolic processes. The company recognized the microbial cell factories as an intangible asset upon the acquisition of Danisco. This intangible asset is expected to contribute to cash flows beyond the foreseeable future and there are no legal, regulatory, contractual, or other factors which limit its useful life.

Pioneer germplasm is the pool of genetic source material and body of knowledge gained from the development and delivery stage of plant breeding. The company recognized germplasm as an intangible asset upon the acquisition of Pioneer. This intangible asset is expected to contribute to cash flows beyond the foreseeable future and there are no legal, regulatory, contractual, or other factors which limit its useful life.