Explainer: The Basics of DNA and Genetic Systems

While there is great diversity among living things, we all have one thing in common—we all rely on a genetic system made up of DNA and/or RNA.

But how do genetic systems work, and to what extent do they vary across species?

This graphic by Anne-Lise Paris explores the basics of DNA and genetic systems, including how they’re structured, and how they differ across species.

Composition of Genetic Systems: DNA and RNA

A genetic system is essentially a set of instructions that dictate our genetic makeup—what we look like and how we interact with our environment.

This set of instructions is stored in nucleic acids, the two main types being deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

While most living things rely on a mix of DNA and RNA for cellular reproduction, some viruses just use RNA to store their genetic information and replicate faster.

DNA is made up of four molecules, known as nucleotides: Adenine (A), Thymine (T), Cytosine ( C), and Guanine (G). These nucleotides are grouped in sets of two, which are called base pairs.

Size of Genomes Across Different Organisms

Human DNA is made up of approximately 3.2 billion base pairs that are tightly wound up and stored in our cells. If you were to unwind and measure the DNA stored in a single human cell, it would be about 2 meters (6.5 feet) long!

This lengthy DNA is stored in pairs of chromosomes. A full collection of chromosomes, or an entire set of genetic information, is referred to as a genome.

Genomes vary in size, depending on the organism. Here is a look at 24 different species and the size of their genomes, from animals and plants to bacteria and viruses:

The Marbled Lungfish has the largest known animal genome. Its genome is made up of 130 billion base pairs, which is about 126.8 billion more than the average human genome.

Comparatively, small viruses and bacteria have fewer base pairs. The Hepatitis D virus has only 1,700 base pairs, while E. coli bacteria has 4.6 million. Interestingly, research has not found a link between the size of a species’ genome and the organism’s size or complexity.

In fact, there are still a ton of unanswered questions in the field of genome research. Why do some species have small genomes? Why do some have a ton of redundant DNA? These are still questions being investigated by scientists today.

Mapped: Which Countries Still Have a Monarchy?

In the wake of Queen Elizabeth II’s death, the question of monarchy is brought sharply into focus.

However, a surprising number of countries have ruling monarchs, and in this visual we break down the kinds of royal leadership across the 43 countries that still have them.

Types of Monarchies

A monarch in the simplest sense is a country’s king, queen, emir, or sultan, and so on. But before diving in, it’s important to break down the distinctions between the types of monarchies that exist today. Generally, there are four kinds:

① Constitutional Monarchy

The monarch divides power with a constitutionally founded government. In this situation, the monarch, while having ceremonial duties and certain responsibilities, does not have any political power. For example, the UK’s monarch must sign all laws to make them official, but has no power to change or reject new laws.

Here are some examples of countries with constitutional monarchies:

🇯🇵  Japan
🇬🇧  United Kingdom
🇩🇰  Denmark

② Absolute Monarchy

The monarch has full and absolute political power. They can amend, reject, or create laws, represent the country’s interests abroad, appoint political leaders, and so on.

Here are some examples of countries with absolute monarchies:

🇸🇿  Eswatini
🇸🇦  Saudi Arabia
🇻🇦  Vatican City

③ Federal Monarchy

The monarch serves an overall figurehead of the federation of states which have their own governments, or even monarchies, ruling them.

Here are some examples of countries with federal monarchies:

🇦🇪  UAE
🇲🇾  Malaysia

Malaysia is a unique form of federal monarchy. Every five years, each state’s royal leaders choose amongst themselves who will be the monarch, or the Yang di-Pertuan Agong, of Malaysia and the respective states. Furthermore, the monarchy is also constitutional, allowing a democratically elected body to govern.

④ Mixed Monarchy

This is a situation wherein an absolute monarch may divide powers in distinct ways specific to the country.

Here are some examples of countries with mixed monarchies:

🇯🇴  Jordan
🇱🇮  Liechtenstein
🇲🇦  Morocco

Interestingly, Liechtenstein is the only European monarchy that still practises strict agnatic primogeniture. Under agnatic primogeniture, the degree of kinship is determined by tracing descent from the nearest common ancestor through male ancestors.

Kings, Queens, Emperors, and Sultans Around the Globe

Now let’s break down the different monarchies country by country:

Constitutional monarchies are undoubtedly the most popular form of royal leadership in the modern era⁠, making up close to 70% of all monarchies. This situation allows for democratically elected governments to rule the country, while the monarch performs ceremonial duties.

Most monarchs are hereditary, inheriting their position by luck of their birth, but interestingly, French president, Emmanuel Macron, technically serves as a Co-Prince of Andorra.

Another unique case is the Vatican’s Pope Francis, who has absolute power in the small independent city⁠—he gained his role thanks to an election process known as a papal conclave.

The Role of Monarchies

One of the most notable and famous ruling monarchies is the United Kingdom’s House of Windsor⁠—also known as Queen Elizabeth II’s family. King Charles III has now ascended to the country’s throne, making him head of state in 15 nations total, including Canada, Australia, and New Zealand.

Many see the benefit in having a stable and consistent form of tradition and decorum at the country’s head of state.

“The Crown is an integral part of the institution of Parliament. The Queen [now King] plays a constitutional role in opening and dissolving Parliament and approving Bills before they become law.” – British Parliament

Japan’s royal family has been a prime example of stability, having reigned in the country for more than 2,600 years under the same hereditary line.

Critiques and the Future of Monarchy

Some claim, however, that there is no function of monarchy in the modern day, and complaints of monarchies’ immense wealth and power are rampant.

For example, according to the Dutch government, King Willem-Alexander’s budget for 2022, funded by the state and thus, taxpayers, comes out to more than €48 million.

Beyond tax dollars, with absolute monarchies there is typically a lack of political freedoms and certain rights. Saudi Arabia, for example, has no national elections. Rather its king, Salman bin Abdulaziz Al Saud, stays in power for life, appoints the cabinet himself, and passes laws by royal decree.

The death of Queen Elizabeth, though, may bring about change though for many of the world’s royally-governed. Since Barbados’ removal of her as head of state in 2021, six other Caribbean nations have expressed the desire to do the same, namely:

🇧🇿  Belize
🇧🇸  The Bahamas
🇯🇲  Jamaica
🇬🇩  Grenada
🇦🇬  Antigua and Barbuda
🇰🇳  St. Kitts and Nevis

The future of monarchy in the 21st century is certainly not a guarantee.