Undergraduate Honors Thesis Projects

Date of Award

Spring 5-4-2025

Document Type

Honors Paper

Degree Name

Zoo and Conservation Science-BA

Department

Biology & Earth Science

Advisor

Dr. Sinn; Dr. Lescinsky

First Committee Member

Dr. Brandon Sinn

Second Committee Member

Dr. Halard Lescinsky

Third Committee Member

Dr. Anthony DeStefanis

Keywords

Axolotl, Genetics, Melanistic, Leukocyte tyrosine kinase

Subject Categories

Animal Sciences | Genetics and Genomics | Higher Education | Research Methods in Life Sciences

Abstract

Ambystoma mexicanum is an aquatic salamander species, commonly known as the axolotl, native to Mexico that is widely researched all over the world. In the wild, these salamanders have brown/black colored skin due to the presence of melanophores and xanthophores with shiny spots due to iridophores. In captivity, however, there are multiple different color morphs (phenotypes) of axolotls including leucistic, melanistic, and copper. Melanoid axolotls have black skin made by mostly melanophores, little xanthophores, and no iridophores. Melanistic genotypes such as melanoid and wild type color morphs are thought to be controlled by a single gene called Leukocyte Tyrosine Kinase (Ltk) (Kabangu, 2023). However, our understanding of the genetics behind these different color morphs remains incomplete.

Eight oligonucleotide primers were developed using Primer3 in order to develop a polymerase chain reaction (PCR) test for the presence of the particular Ltk alleles. The amplification and phenotypic specificity of the primers was tested on melanistic, wild type, white, and albino axolotls. Unfortunately, none of the primers were successful in amplifying only their target Ltk alleles. Because the axolotl genome is 32 billion base pairs long and extremely repetitive, many sequences are repeated throughout the genome making it very difficult to create allele-specific primers for the targeted gene. These results suggest that a longer reverse primer sequence unique to Ltk could be a potential way to achieve allele-specific amplification in future work.

Licensing Permission

Copyright, all rights reserved. Fair Use

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Acknowledgement 2

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