Practical exercises in Plant Biodiversity and Breeding (BI1103) Jonas RoosTom MartinLuisa Ghelardini
General aim of these labs: To use recombinant inbred lines (RIL) as an example of genetic variation, and to gain practical experience in working with plants. Specific aim: To map the ERECTA gene in Arabidopsis thaliana. a) Looking at plants ⇒ phenotype b) Looking at genetic markers ⇒ genotype c) Correlating genotype and phenotype ⇒ location of ERECTA gene
Arabidopsis thaliana Columbia (Col-0)Landsberg erecta (Ler)
Petiole (short/long) Leaf (round/elongate)
Large inflorescence Long siliques Col-0Ler inflorescence
All of these features are controlled by a single gene: ERECTA (ER) - Your task is to find out where this gene is located.
Recombinant Inbred Lines (RIL) Each RIL is a unique mix of Col-0 and Ler. 8 generations of inbreeding ⇒ homozygous at all loci
- Each RIL a unique mix of Col-0 and Ler DNA. - Correlate each genotype with the phenotype. - Quantitative Trait Locus (QTL) mapping. QTL mapping – correlate genotype and phenotype
- Plants will have either “Col-0” or “Ler” phenotype. - “Col-0” phenotype ⇒ Col-0 version of ERECTA gene - “Ler” phenotype ⇒ Ler version of ERECTA gene QTL mapping – correlate genotype and phenotype
Genotype - genetic markers
Genetic map of Arabidopsis thaliana - Five chromosomes, about 50 markers Lister and Dean (1993) The Plant Journal 4:
Indel markers - The maker order and location is identical in Col-0 and Ler. - However, the markers themselves are different. - Can be either Col-0 version or Ler version. m291 Ler m291 Col
Indel (insertion/deletion) markers - Amplified with PCR - Identified on an agarose gel LerCol-0 m291
Summary 1.Plant out RIL, compare phenotype with Col-0 and Ler. - “Ler” phenotype ⇒ Ler version of ER - “Col-0” phenotype ⇒ Col-0 version of ER 2.Identify RIL genotype (indel markers) 3.Compare phenotype and genotype (QTL mapping) ⇒ location of ER.