Some seeds are transformed by a mechanism that will be discussed on Friday. To identify the transformed seed, the seed is plated on agar containing kanamycin where normal seed germinate and die, while transformed seed form viable seedlings that can be transplanted and grown in greenhouse pots. Much is known from genetic analysis of transformed plants. We know that T-DNA can insert in all the different chromosomes that make up a genome and within each chromosomes at many chromosomal positions. One or multiple copies of T-DNA are inserted at each chromosomal locus.
Insertion can occur at one or more loci but never in both alleles of the same locus.
When a plant is transformed by two or more different loci, these are usually unlinked. Below is a figure illustrating transformation of a plant cell resulting in a single T-DNA locus. For simplicity, two chromosome pairs are show, one red and one green. Note that the first generation transformant is heterozygous. Since the KanR gene is dominant, this individual will be resistant to kanamycin.