18Quant - 1/16 bbhh transgressive variation (x i mean) 2...

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Quantitative Genetics phenotype Multifactorial traits nature vs. nuture identical (monozygotic) twins fraternal (dizygotic) twins concordance discordance IDDM Concordant pairs Discordant pairs Conclusion identical twins 20 30 fraternal twins 4 46 Polygenic traits polygenic trait A tomato plant with ripe fruit averaging 300g BBHH is crossed with a tomato plant with ripe fruit averaging 200g bbhh. The F 1 s are BbHh and their fruit average 250g. The F 2 s are B H Overall 1/4 HH 1/16 BBHH 1/4 Hh 1/16 BBHh 1/4 BB 1/4 hH 1/16 BBhH 1/4 hh 1/16 BBhh 1/4 HH 1/16 BbHH 1/4 Hh 1/16 BbHh 1/4 Bb 1/4 hH 1/16 BbhH 1/4 hh 1/16 Bbhh 1/4 HH 1/16 bBHH 1/4 Hh 1/16 bBHh 1/4 bB 1/4 hH 1/16 bBhH 1/4 hh 1/16 bBhh 1/4 HH 1/16 bbHH 1/4 Hh 1/16 bbHh 1/4 bb 1/4 hH 1/16 bbhH 1/4 hh
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Unformatted text preview: 1/16 bbhh transgressive variation (x i mean) 2 variance: V = n 1 phenotypic, genetic, and environmental variances: V P = V G + V E broad-sense heritability: H 2 = V G / V P Problem: Inbred mouse strain DB2 has an LDL cholesterol concentration with mean 75 mg/dL and variance 400. Inbred mouse strain C57BL/6 has an LDL cholesterol concentration with mean 100 mg/dL and variance 410. The F1s produced from a DB2 x C57BL/6 have a mean LDL concentration of 82 mg/dL with variance 425. These hybrids, when interbred, produced mice with a mean LDL concentration of 89 mg/dL and a variance of 820. All mice were housed under identical environmental conditions. Calculate H 2 . 27...
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