Correlated responses in body composition based on selection for different indicator traits in mice.

Abstract

Correlated responses in whole-body composition were determined in 12-wk-old male mice from replicate lines selected for 12 generations for high (HF) or low (LF) epididymal fat pad weight as a percentage of body weight (EPID) and high (HL) or low (LL) hind carcass weight as a percentage of body weight. The HF and LF lines diverged (P less than .01) in body fat percentage (FAT) and subcutaneous depot fat by 93 and 71%, respectively, of the control line (RC) mean. EPID increased (P less than .01) proportionately more than FAT in the HF line; EPID decreased (P less than .01) proportionately less than FAT in LF. Protein, fat and water as a percentage of empty body weight showed negative correlated responses (P less than .01) due to selection for EPID, but lean body mass, body weight and body length had positive correlated responses (P less than .01). Correlated responses of fat-free protein and ash percentage were minor. Correlated responses in HL and LL were the mirror images of those in HF and LF, but they generally were of smaller magnitude. The results indicate that, although there are high positive genetic correlations between fat depots in mice, local control of lipogenesis and(or) lipolysis exists at different sites of fat deposition. Further, the lack of correlated responses in fat-free percentage of protein (and percentage of ash) suggests that additive genetic variances are low for these traits and(or) the genetic correlations of these traits with the selection criteria are low.

Quantitative trait loci for individual adipose depot weights in C57BL/6ByJ x 129P3/J F2 mice

“…In mice, the retroperitoneal adipose depot increases in response to an energy-dense diet less than does the gonadal depot (Bachmanov et al 2001). Taken together, genetic and physiologic studies suggest that adipose depots differ in weight and function and that individual differences in adipose depot weight are at least partly due to genotype (Allen and McCarthy 1980;Eisen and Coffey 1990;Festing 1979;West et al 1994).…”

Adiposity QTLAdip20decomposes into at least four loci when dissected using congenic strains

“…This is a simple measurement method, and our expectation was 312 that its genetic architecture would be less complex than for whole-body obesity. We specifically 313 chose the gonadal over other depots because it is the heaviest [13,14,73] and a proxy for 314 overall adiposity [77,78]. However, despite all these complexities, both mouse and human 315 genetic approaches point to the same underlying mammalian biology: QTL regions found here 316 contain many mouse orthologues for obesity genes identified by human genome-wide 317 association studies.…”

Multitrait restricted and desired gains selection indices designed to change growth and body composition in mice1

“…Further, P rasetyo and E isen (1989) reported high positive correlated responses in other fat depots, including ages other than 12 weeks, the age of high‐low selection for EF/BW (E isen , 1987b). However, selection for EF/BW led to a change in the ratio of EF to total fat in two studies (H astings and H ill 1989; E isen and C offey 1990), suggesting that local control of fat metabolism exists at different sites of fat deposition. In other lines, selected divergently for HC/BW, positive correlated responses were observed in protein percentage and lean body mass as a percent of body weight (E isen and C offey 1990).…”

“…However, selection for EF/BW led to a change in the ratio of EF to total fat in two studies (H astings and H ill 1989; E isen and C offey 1990), suggesting that local control of fat metabolism exists at different sites of fat deposition. In other lines, selected divergently for HC/BW, positive correlated responses were observed in protein percentage and lean body mass as a percent of body weight (E isen and C offey 1990). Collectively, these results indicate that in mice EF and HC are useful indicator traits of fat and lean tissue weight, respectively.…”