Changes in Genetic Variances and Covariances: G Whiz!

Frank H. Shaw; Ruth G. Shaw; Gerald S. Wilkinson; Michael Turelli

doi:10.2307/2410450

Linkage disequilibrium and genetic variances under mutation-selection balance.

Genetics ◽

10.1093/genetics/121.4.857 ◽

1989 ◽

Vol 121 (4) ◽

pp. 857-860 ◽

Cited By ~ 1

Author(s):

A Hastings

Keyword(s):

Linkage Disequilibrium ◽

Mutation Rate ◽

Genetic Variance ◽

Harmonic Mean ◽

Recombination Rates ◽

Genetic Variances ◽

Locus Selection

Abstract I determine the contribution of linkage disequilibrium to genetic variances using results for two loci and for induced or marginal systems. The analysis allows epistasis and dominance, but assumes that mutation is weak relative to selection. The linkage disequilibrium component of genetic variance is shown to be unimportant for unlinked loci if the gametic mutation rate divided by the harmonic mean of the pairwise recombination rates is much less than one. For tightly linked loci, linkage disequilibrium is unimportant if the gametic mutation rate divided by the (induced) per locus selection is much less than one.

130 Utilization of Nutrack to Assess Variance Components and Heritability of Activity Traits

Journal of Animal Science ◽

10.1093/jas/skab054.030 ◽

2021 ◽

Vol 99 (Supplement_1) ◽

pp. 17-17

Author(s):

Lexi M Ostrand ◽

Melanie D Trenhaile-Grannemann ◽

Garrett See ◽

Ty B Schmidt ◽

Eric Psota ◽

...

Keyword(s):

Animal Model ◽

Mixed Models ◽

Variance Components ◽

Average Speed ◽

Genetic Variances ◽

Sow Longevity ◽

Selection Decisions ◽

Recorded Data ◽

Residual Variances ◽

And Behavior

Abstract Overall activity and behavior are integral components of sows remaining productive in the herd. This investigation studied overall activity of group housed replacement gilts and the heritability of various activity traits. Beginning around 20 wk of age, video recorded data of approximately 75 gilts/group for a total of 2,378 gilts over 32 groups was collected for 7 consecutive d using the NUtrack System, which tracks distance travelled (m), avg speed (m/s), angle rotated (degrees), and time standing (s), sitting (s), eating (s), and laying (s). The recorded phenotypes were standardized to the distribution observed within a pen for each group. The final values used for analysis were the average daily standardized values. Data were analyzed using mixed models (RStudio V 1.2.5033) including effects of sire, dam, dam’s sire and dam, dam’s grandsire and granddam, farrowing group, barn, pen, and on-test date. Sire had an effect on every activity trait P < 0.001), and dam had an effect on average speed (P < 0.001). The dam’s sire had an effect on all activity traits (P < 0.001) and the dam’s grandsire had an effect on average speed (P < 0.001). Heritabilities and variance components of activity traits were estimated in ASReml 4 using an animal model with a two-generation pedigree. Genetic variances are 0.17 +/- 0.029, 0.19 +/- 0.034, and 0.11 +/- 0.024, residual variances are 0.37 +/- 0.023, 0.41 +/- 0.027, and 0.41 +/- 0.022, phenotypic variances are 0.54 +/- 0.018, 0.60 +/- 0.020, and 0.52 +/- 0.016, and heritabilities are 0.32 +/- 0.048, 0.32 +/- 0.049, and 0.21 +/- 0.044 for average speed, distance, and lie respectively. NUtrack offers potential to aid in selection decisions. Given the results presented herein, continued investigation into these activity traits and their association with sow longevity is warranted.

Genetic variances due to imprinted genes in cattle

Journal of Animal Breeding and Genetics ◽

10.1046/j.1439-0388.2002.00323.x ◽

2002 ◽

Vol 119 (3) ◽

pp. 154-165 ◽

Cited By ~ 24

Author(s):

TH. ENGELLANDT ◽

B. TIER

Keyword(s):

Imprinted Genes ◽

Genetic Variances

Sex‐specific additive genetic variances and correlations for fitness in a song sparrow ( Melospiza melodia ) population subject to natural immigration and inbreeding

Evolution ◽

10.1111/evo.13575 ◽

2018 ◽

Vol 72 (10) ◽

pp. 2057-2075 ◽

Cited By ~ 12

Author(s):

Matthew E. Wolak ◽

Peter Arcese ◽

Lukas F. Keller ◽

Pirmin Nietlisbach ◽

Jane M. Reid

Keyword(s):

Melospiza Melodia ◽

Song Sparrow ◽

Genetic Variances

Variation during growth of twin cattle

Animal Science ◽

10.1017/s0003356100038253 ◽

1967 ◽

Vol 9 (1) ◽

pp. 35-60 ◽

Cited By ~ 4

Author(s):

C. S. Taylor ◽

Jean Craig

Keyword(s):

Genetic Variation ◽

Body Part ◽

Body Measurements ◽

Body Parts ◽

Genetic Variances ◽

Average Value ◽

Coefficients Of Variation ◽

Rate Of Increase ◽

Early Maturing ◽

Degree Of Maturity

Phenotypic variances within pairs of monozygotic and dizygotic twin heifers and also genetic variances and heritabilities were calculated for 12 linear body measurements at a sequence of eight ages up to two years old. The 60 pairs of fraternal and 60 pairs of identical twins used were reared as part of a larger uniformity trial in which feeding was effectively ad libitum throughout.Size differences between members of DZ twin pairs were found to be approximately normally distributed with about the same variance for all breeds and crosses. The variance within DZ pairs increased strongly with age, with a marked increase between 9 and 12 months of age and with most body measurements showing a broadly similar trend. On a logarithmic scale DZ variances increased roughly linearly with degree of maturity and at about the same rate in each body measurement. Coefficients of variation within DZ pairs corrected for measuring error had an average value of 2%. They did not change greatly with age, and were roughly the same for most body measurements although width measurements tended to be more variable than average.Coefficients of variation within MZ pairs had a corresponding overall average of 1·4%; they declined rapidly with age from 2·0% to 1·1%, were roughly the same for all body measurements, but at early ages tended to be greater in late than in early maturing body parts. However, they showed no association with the earliness of maturing of a body part provided variation was measured at the same degree of maturity for each body part.Genetic variation increased rapidly with age in all body measurements. The rate of increase with age was greater for late than for early maturing parts. The rate of increase with degree of maturity, however, was about the same for all body measurements. Coefficients of genetic variation increased slowly with age; they had an average value of 1·6%.Estimates of heritability are given at a sequence of eight ages for each of 12 body measurements. They increased strongly with age from 0·14 on average at three months of age to 0·67 on average at two years of age. At any fixed age, early maturing body parts tended to have higher heritabilities than later maturing body parts. However, if heritability was measured at the same degree of maturity in each body part, early and late maturing parts had about equal heritabilities.The present results are compared with those obtained from twin cattle studies in New Zealand, Sweden and Wisconsin, U.S.A.Inferences from twins about genetic variances and heritabilities for unrelated animals are discussed.

The Estimation of Maternal Genetic Variances

Biometrics ◽

10.2307/2529273 ◽

1976 ◽

Vol 32 (4) ◽

pp. 903 ◽

Cited By ~ 47

Author(s):

Robin Thompson

Keyword(s):

Genetic Variances

ENTRIES PERFORMANCE OF BREAD WHEAT AND ESTIMATION OF PHENOTYPIC AND GENETIC VARIANCES AND GENEIC CORRELATION

Mesopotamia Journal of Agriculture ◽

10.33899/magrj.2007.26446 ◽

2007 ◽

Vol 35 (1) ◽

pp. 117-123

Author(s):

Ahmed A. Ahmed

Keyword(s):

Bread Wheat ◽

Genetic Variances