From The Polyploidy Portal

MapPlants

Ed Himelblau, Asst. Professor of Biology, California Polytechnic San Luis Obispo email, Tel: 805-756-2826


MapPlants is a plant-based laboratory for undergraduate genetics and molecular biology students. Students grow plants, score a mutant phenotype, extract DNA from the plants, and use molecular markers to map the mutant locus.

MapPlant seeds will be sent to you upon request. You will receive several lines: 1) “MapPlant Parent ap/gl in Ler” is the Landsberg erecta parent. This line is homozygous for the gl1 and ap1 mutation. 2) “MapPlant parent Col” is the wildtype Columbia parent. 3) The parents described above were crossed to generate an F1. The F1 was allowed to self-pollinate to create an F2. The tube labeled “MapPlant F2: ap/gl in Ler X Col” contains these F2 seeds.

It is recommend that each student or each lab group grow 20-30 of the F2 plants. You should grow one pot each of the two parental lines for the students to observe.

You will need to order several PCR primers. All of the MapPlants Primers can be found on The Arabidopsis Information Resource (TAIR). Simply enter “mapplant” into the search window and change the search field to “Marker”:

There are six sets of MapPlant primers. I recommend you order the following: MP1.1 (this is tightly linked to the GL2 locus) MP3.3 (this is tightly linked to the GL1 locus) MP5.1 (this is tightly linked to the TTG locus) (Note: these are all CAPS markers. All use the same restriction enzyme, XbaI…so you will have to order a tube of XbaI restriction enzyme too. MP3.1 and MP3.2 are BamHI CAPS markers.)

The way I’ve presented MapPlants to students begins by allowing them to see the glabrous phenotype segregating (3:1) in their F2 plants. I then tell them that there are three genes that, when mutated, produce this phenotype (GL1, GL2 and TTG). The students use the linked markers to determine that it is GL1 that is mutated in the plants they have grown.

Supporting materials for MapPlants

These materials assume you are familiar with growing Arabidopsis, amplifying DNA using PCR, and analyzing DNA using agarose gel electrophoresis. The materials consist primarily of handouts I created when I taught MapPlants in my class at Southampton College. Please don’t hesitate to contact me if you have any question about the technical details of the lab. I have included the following files:

MapPlants_Intro.pdf: The introduction

chromosome map.pdf: a map showing the location of the MapPlant markers and the genes that, when mutated, cause a glabrous phenotype. (GL1 is mutated in the population I sent you.)

At DNA ext: Protocol for DNA extraction as MSWord file. Also, the PCR conditions I use are listed.

Map1: MapPlants Lab 1. This MSWord file introduces students to Arabidopsis. It asks students to use TAIR to identify the chromosomal location of GL1, GL2 and TTG. The concept of markers (CAPS markers in particular) are discussed.

Map2: MapPlants Lab 2. This MSWord file explains how to perform a restriction enzyme digestion and provides a worksheet where students can record their data.

map based cloning1.pdf: This shows the genetic history of the seeds. The two parents are shown on top with color-coded chromosomes. The F1 and a group of F2s are also shown (The pictures indicate which of the F2s are glabrous). I give the students this and ask them “what produces the ‘patchwork’ chromosomes of the F2?” At the bottom of the page, the glabrous F2s are grouped together. Based on the chromosomes, I ask “which segment of chromosome must contain the mutation that causes the phenotype?” (The second from the bottom is the only segment that is homozygous for Ler DNA in all glabrous F2s.)

Map based cloning2.pdf: this expands on the idea of the previous file. Here two markers are added. Students fill in the “gels” to see how the results differ using a linked and unlinked marker.

Pop A MP 3.3.jpg
This gel image shows the genotypic analysis of the parents and six glabrous F2 plants with marker 3.3. This marker is linked to the GL1 locus. The photo reveals cosegragation of the marker and the mutant allele.
Pop A MP 5.1.jpg
This gel image shows the genotypic analysis of the parents and six glabrous F2 plants with marker 5.1. This marker is linked to the TTG locus. The photo reveals that the marker and the mutant allele assort independently.
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