Presentation on theme: "Criteria for choosing strains: 1)Encompass Maximum Genetic Diversity 2)Include Sequenced Strains 3)Favor Common Strains Presentation by Dr. James Cheverud."— Presentation transcript:
Criteria for choosing strains: 1)Encompass Maximum Genetic Diversity 2)Include Sequenced Strains 3)Favor Common Strains Presentation by Dr. James Cheverud CTC Satellite Meeting of the IMGC San Antonio, November 17, 2002
Relationships Among Mouse Strains Historical relationships among mouse strains can be quite complex, involving independent strain origins, bifurcations, and reticulation. Rather than being best represented by a branching tree, relationships may be more accurately modeled as a star, with all strains arising from a common single origin. This is similar to the relationships expected among RI strains originating from a single cross.
1)We measured genetic diversity using percent similarity among all strain pairs: S = (# of shared microsatellite loci/total # of loci) 2)We used Non-Metric Multidimensional Scaling to order the strains in a 4- Dimensional Space. This procedure minimizes the squared deviation of the predicted 4D distances from the observations. 3)Contrasts between extremes along the dimensions indicate specific sets of strains that can encompass the diversity among all strains. Measuring and Modeling Diversity
Multidimensional Scaling Results Dim.Stress% Variance 3D D D
First Two Dimensions of 4-Dimensional Solution. Extreme Strains on Dimension: 1: RIIIS/J DBA/2J 2: KK/HIJ BALB/cJ DIM2DIM2
Last Two Dimensions of 4-Dimensional Solution. Extreme Strains on Dimension: 3: AKR/J – SM/J 4: 129x1/SvJ – RIIIS/J DIM4DIM4
Strains Chosen for CTC 8-Way Intercross (Jim’s initial analysis, Nov 2002) C57BL/6J (extreme on 5 th Dimension) RIIIS/J DBA/2J BALB/cJ SM/J 129X1/SvJ AKR/J KK/HIJ This set maintains about 90% of the variation in the 4-Dimensional solution and thus about 75% of the genetic diversity of standard mouse strains