Bio 181 student photo with DNA Christmas tree projects.

DNA Christmas Tree Project

Homologous Chromosomes

This DNA structure symbolizes homologous chromosomes, where one chromosome from the mother and one from the father pair up during fertilization. Humans possess 23 sets of homologous chromosomes in each cell, with identical genes in corresponding positions. The combination of genes from the mother’s and father’s chromosomes determines an individual’s appearance. The human body comprises approximately 37 trillion cells. 

How the Project Came to Life

In November 2019, students from the BIO181 biology class initiated a project crafting the first paternal chromosome in blue in the images. Initially focused on enhancing their grasp of DNA structure, the project transformed into the creation of a distinctive DNA Christmas tree. Over three weeks, students met regularly for about 2 hours per session, using recycled materials like cardboard boxes, styrofoam, and wire. During construction, they explored DNA intricacies, uncovering antiparallel strands, nucleotide structure, and complementary sequences (A=T and CG), resulting in an impressive double helix with major and minor grooves. The final creation featured a flawless B-form DNA structure, encapsulating 10 to 11 nucleotides in a single complete turn. 

Completion of the Set of Homologous Chromosomes

Four years after the inception of the paternal chromosome in 2019, a new group of BIO181 students, in 2023, embarked on constructing the maternal chromosome depicted in pink in the images, thus finalizing the set of homologous chromosomes. Witnessing the students engage in discussions about DNA structure, educate one another, and exchange ideas during the collaborative construction was a source of great pride. 

This project is believed to be the first DNA construction representing homologous chromosomes in the form of a Christmas tree. The remaining 22 sets of chromosomes will be constructed by future BIO181 students, culminating in the completion of all 23 sets of chromosomes.