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Titolo:
Components of heterosis for growth traits and litter size in line crosses of mice after long-term selection
Autore:
Mohamed, SA; Rottmann, O; Pirchner, F;
Indirizzi:
TUM, Dept Tierwissensch, Wissensch Zentrum Weihenstephan, D-85350 FreisingWeihenstephan, Germany TUM Freising Weihenstephan Germany D-85350 reisingWeihenstephan, Germany Univ Garyouns, Fac Sci, Dept Zool, Benghazi, Libya Univ Garyouns Benghazi Libya youns, Fac Sci, Dept Zool, Benghazi, Libya
Titolo Testata:
JOURNAL OF ANIMAL BREEDING AND GENETICS-ZEITSCHRIFT FUR TIERZUCHTUNG UND ZUCHTUNGSBIOLOGIE
fascicolo: 4, volume: 118, anno: 2001,
pagine: 263 - 270
SICI:
0931-2668(200108)118:4<263:COHFGT>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
DOMINANCE;
Keywords:
components of heterosis; epistasis; dominance; litter size; mouse growth;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
20
Recensione:
Indirizzi per estratti:
Indirizzo: Rottmann, O TUM, Dept Tierwissensch, Wissensch Zentrum Weihenstephan, D-85350 FreisingWeihenstephan, Germany TUM Freising Weihenstephan Germany D-85350 nstephan, Germany
Citazione:
S.A. Mohamed et al., "Components of heterosis for growth traits and litter size in line crosses of mice after long-term selection", J ANIM BR G, 118(4), 2001, pp. 263-270

Abstract

Strains selected for 54 generations for large 8-week weight (N8, S8), for small weight (N6, S6), for high control strains (N9, 3-5-week gain and low 8-week weight (NI) as well as unselected randomly mate S9) were crossed, and F-1, F-2 and both back crosses created. N strains are derived from a NMRIbase, S strains from a synthetic four-way cross among inbred lines. Heterosis for 8-week weight (8-ww) was some 6%, but 30% for 3-5-week gain and it was on average negative (22%) for 5-8-week gain. When epistatic effects were taken into account, it appeared that heterosis for 8-ww was largely due to beneficial effects of non-parental gene combinations, i.e. additive x additive epistatic effects were negative. These non-parental combinations neutralized the mostly negative dominance effects. The latter were mostly positive for early gain but in all 9 line crosses negative for late gain. The digenic effects of the non-parental origin were not large enough to balance the negative dominance effects for late gain, so that heterosis was negative. It appears therefore that early and late gain are affected by different sets of genes. Maternal additive effects on 8-ww and early gain are smaller than direct additive effects but mostly of similar sign. For late gain there appears to Se no connection with direct additive effects. Direct litter heterosis was almost 50% but much of this was due to positively actin recombinational gene combinations, while direct litter dominance was mostly negative. Maternal additive effects on litter size differed depending on whetherthey were estimated from dams with crossbred or with purebred litter. Heterosis was small in crosses between control strains. Heterosis caused by recombinant gene pairs should be amenable to improvement by selection.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 19/09/20 alle ore 09:25:12