Related Experiment Video
Updated: Jul 17, 2026

Agrobacterium-Mediated Immature Embryo Transformation of Recalcitrant Maize Inbred Lines Using Morphogenic Genes
Published on: February 14, 2020
Exceptionally High Levels of Restriction Site Polymorphism in DNA near the Maize Adh1 Gene
M A Johns1, J N Strommer, M Freeling
1Department of Genetics, University of California, Berkeley, California 94720.
Abstract:
Restriction maps have been prepared for the chromosomal region near seven biochemically and genetically distinct maize alcohol dehydrogenase-1 (Adh1) alleles using a small cDNA probe for Adh1. Five restriction sites spanning about 4 kb in and near the Adh1 transcription unit appear identical in all seven alleles. Outside this conserved region, variation in restriction site position is the rule. Six of the seven alleles are distinguishable, and the alleles appear to fall into four groups. The DNA flanking the 1S-type alleles seems to share no restriction site homology with the DNA near the 1F-type alleles. Several hypotheses are put forward to explain how such high levels of polymorphism could have arisen in a species that has been domesticated for only about 10,000 years.
Related Concept Videos
Position-effect Variegation
Exon Recombination
Exon shuffling follows “splice frame rules.” Each exon has three reading...
Restriction Enzymes
The host bacteria protect their own genomic DNA from these enzymes by methylating these sites. Some...
Trihybrid Crosses
Some of Mendel’s crosses examined three pairs of contrasting characteristics. Such a cross is called a trihybrid cross. A trihybrid cross is a combination of three individual monohybrid crosses. For example, plant height (tall vs. short), seed shape (round vs. wrinkled), and seed color (yellow vs. green).
The F1 generation plants of a trihybrid cross are heterozygous for all three traits and produce eight gametes. Upon self-fertilization, these gametes have an equal chance to...

