Table 2

Evaluation of methods for swine transgenesis

Pronuclear (naked DNA)

Pronuclear (transposon)a

SCNT (PFF)

Lentiviral


Live-born/embryo manipulated

10% to 15%

ND

0.05% to 1.2%

18% to 27%

Transgenic per live-born

+

++

+++

++

Integration preference

Random

Random/class specific

Random or targeted

Gene coding regions

Null/hypomorph

RNAi/DN

RNAi/DN

Gene targeting/RNAi/DN

RNAi/DN

Cargo size limitationsb

ND

ND

ND

About 8 kilobases

Integrations per live-born

Typically 1

1 to 10

Typically 1

1 to 20

Mosaicism

Often

Often

Seldom

often

Ease of vector production

++

++

++/(± HR constructs)

+

Concatemer instability

Yes

No

Yesc

No

Precision (to the base pair)

No

Yes

Noc

Yes

Homologous recombination

No

No

Yes

No

Genome aberrations

Yes

No

No

No

Heritable expression

++

+++

++d

++

Preimplantation screen

±

±

++e

±

Selection required

No

No

Yes

No


aAs observed previously in mice. bIncreasing size invariably decreases efficiency. cTargeted alleles are stable. dMosaicism observed in clones of clones [200]. eExpression in SCNT donor cells does not ensure expression in animal. DN, dominant negative translocations; HR, homologous recombination; ND, not determined; PFF, porcine fetal fibroblasts; RNAi, RNA interference; SCNT, somatic cell nuclear transfer.

Clark et al. Genome Biology 2007 8(Suppl 1):S13   doi:10.1186/gb-2007-8-s1-s13