ANSC 313 Lecture Notes - Lecture 20: Quantitative Trait Locus, Dopamine Receptor D4, Embryo Transfer
LECTURE 9!
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DNA Tests for use in Selection !
Example Traits:!
diseases ( many in dogs : some in cattle, horses, ect.)!ā¢
coat colour!ā¢
traits of economic importance !ā¢
DNA test for quantitative traits!
Example traits:!
behaviour!ā¢
meat quality !ā¢
!
Canadian Beef reference herd!
130 calves in 17 embryo transfer families!ā¢
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Motion Measuring Device !
weight and motion is calculated!ā¢
used for quantitating behaviour!ā¢
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Temperament!
measured at weaning at 6 months!ā¢
held on an electronic platform scale for 1 minute!ā¢
visually isolated!ā¢
amount of movement quantiļ¬ed !ā¢
!
habituation!
diļ¬erence in movement scores between weaning and 3 months later!ā¢
handled every other week through this device during the interim !ā¢
!
ended up with most animals going down in movement on the device from habituation!
there was lots of variation in this!ā¢
!
Because there were groups of siblings, heritability could be calculated !
behaviour traits are low heritability!ā¢
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Quantitative trait Loci (QTL) Mapping!
studies use DNA markers to try to ļ¬nd genes involved in traits that are considered polygenic !ā¢
need up ļ¬nding 7 diļ¬erent genes!ā¢
!
in other species!
mouse!
emotionality !ā¢
DRD4!ā¢
Horse!
curiosity!ā¢
vigilance!ā¢
DRD4!ā¢
dog!
agression !ā¢
Document Summary
Example traits: diseases ( many in dogs : some in cattle, horses, ect. ) coat colour traits of economic importance. Motion measuring device weight and motion is calculated used for quantitating behaviour. 130 calves in 17 embryo transfer families measured at weaning at 6 months held on an electronic platform scale for 1 minute visually isolated amount of movement quanti ed. Because there were groups of siblings, heritability could be calculated behaviour traits are low heritability. Quantitative trait loci (qtl) mapping studies use dna markers to try to nd genes involved in traits that are considered polygenic need up nding 7 di erent genes in other species mouse emotionality. Candidate gene approach leptin was shown to a ect fat deposition in mice called the obese gene. Gene sequence di erence in bulls leptin mutation identi ed in cattle. C to t change which a ected of the hormone shape.
