Welcome back to my blog everyone! This has been a really exciting experience for many of us on learning so much about the mysterious and captivating Monarch Butterfly. Many interesting topics were shared along with getting to know this type of butterfly as a whole. What can actually be more interesting is digging deeper and getting to know researchers findings.

An article from Nature Research Journal; “The Genetics of Monarch Butterfly Migration and Warning Colouration” talks about the history and genetic basis of evolutionary migration and warning colouration. This insect is most popular for its migration patterns, but have you ever wondered what really makes them actually behave this way? This article goes in depth about the genes and pathways that are associated with this question, so let’s get started!

Introduction

The Monarchs have been migrating annually each fall from North America to Mexico for many many years, but the thing is that not all of Danaus Plexippus butterflies migrate, so the experimenters used comparative population genomics in order to identify migratory behavior shifts. They were first settled in Portugal then dispersed to Spain and Morocco. The ancestral origin, which in North America began to grow more populations due to an increase in milkweed and migration.

Fig.1: When the Atlanta and Pacific populations split, there was a significant decrease in population. 

Methods and Materials

Researches found that there were many reasons on molecular genetics associated with migrations such as circadian rhythms or metabolism but the main one they associated it with was natural selection. The region tested had low sequence diversity in North America finding 536 genes associated with migration. Natural selection was found to have derived allele frequency in migration associated genomic regions. This research suggested that the ancestors for D. Plexippus and D. Erippus was migratory. D. Erippus is a non-migratory butterfly but the derived alleles showed that this also had a migratory pattern. 

Fig. 2b: Dispersal events in South America, the Pacific and Atlantic had an extreme outlier in which they shared a gene called a haplotype was different than the one in North America which was present at a way lower frequency. 

Collagen IV is a key component for muscle morphogenesis and function, so… when this was observed in the PBS. “Migratory and non-migratory haplotypes differed by 51 nucleotide substitutions in the coding sequence of collagen IV a-1, resulting in 15 amino acid substitutions.” D. Plexippus which is the migratory monarch, had high difference in a subsection of its genes when compared to other species. Kettin, a flight muscle gene was also found higher in migratory butterflies. 

Hypothesis

The researchers hypothesis was that these flight muscle genes were specific to the different types of muscle functions in migratory and non-migratory butterflies. Consequentially with this hypothesis, they found that Collagen IV was down-regulated and that natural selection was mainly focused on flight efficiency and long distance flight. To support their findings, their observations showed that changes in flight muscles have resulted in conserving energy and that metabolic rates were lower in the migratory population. 

Discussion

Overall, in this observational  experiment, there were many unexpected answers, but also answers that were tied with a lot of other factors such as flight muscles and dispersal abilities. One thing that was lacking in this observation was the sequence divergence in glycolytic enzymes associated with the metabolic rates. Because the migratory population required such long distances, this induced natural selection to call for reduced flight metabolism. What stands out to me about this experiment is how looking for a specific coding in a particular gene can differentiate whether one species would travel farther than the other, and knowing how they will be able to adapt to certain situations. The Monarchs overall have been decreasing over the years due to many things such as deforestation or the lack of milkweed plants. This topic about monarch migration ties in with a lot other species in the world that are endangered due to the lack of resources or the animals habitats being destroyed. That’s why its important to conserve their habitats and their foods. 

Well, that is all for now on our journey, but don’t be upset because now, you have information about this great animal you never knew about. 

Vocab:

Haplotypes: A set of DNA variations, or polymorphisms, that tend to be inherited together

PBS: Population-branch statistic

 

Web Cited:

Zhan, Shuai, and Kristjan Niitepo˜ld. “The Genetics of Monarch Butterfly Migration and Warning Colouration.” Nature: International Journal of Science, 16 Oct. 2014, www.nature.com/articles/nature13812.