Bombay Blood Group

- A curious adult from the US

July 13, 2018

Perhaps you have heard of the “blood type gene”. The blood type gene can come in three different versions: A, B or O. The versions you inherit determine whether your blood is type A, type B, type AB, or type O.

Appropriately, the blood type gene is named ABO. When we talk about the genetics of blood type, we typically only refer to the ABO gene. And that’s okay. Usually we don’t need to go into greater detail.

A matter of inheritance

It’s worth noting that the Bombay blood group is quite rare. It was only first discovered in Bombay (now Mumbai) in 1952. It affects one person out of 10,000 in India. It is a bit more common in Taiwan, where it affects one person in 8,000. 

It’s even rarer in other parts of the world! Among people of European ancestry, Bombay blood group is literally a one in a million event.

But as rare as it might be, it does happen. And when it happens, it can result in unexpected patterns of inheritance.

The versions of FUT1 are called “H” and “h” for a reason. When the “H” version of FUT1 attaches a sugar to the chain, the chain is called the “H antigen”. When the broken “h” version of FUT1 fails to attach a sugar to the chain, the H antigen is not formed.

The “H” version of FUT1 is dominant to the “h” version. If you get one working “H” version of FUT1, it is enough to do all the work. The blood cells all get the H antigen.

Jewish Ancestry

-A curious adult from California

July 9, 2018

Hi! Interpreting ancestry tests can be a bit tricky. The short answer to your question is that it’s possible your ancestry is from Israel, but it’s not guaranteed…there are other possibilities. 

We’ll break this down into two parts: 

Jewish ancestry is unique and complex

There are many Jewish populations throughout Europe and the Middle East. Each of those populations is quite genetically distinct from both each other and from non-Jewish populations. 

Historically, Jewish people have tended to marry other people in their community. This plays a big role in making individuals of a Jewish community genetically similar to each other. At the same time, it differentiates them from neighboring non-Jewish populations, even if they are geographically close.

How ancestry tests work

- A curious adult from California

July 9, 2018

This is a great question! Ancestry tests are becoming really popular now, thanks to companies like 23andme, MyHeritage, and AncestryDNA (just to name a few). So, it’s good to ask the important question, how do they figure out where your ancestors are from just by checking out your saliva!?

Ancestry test results aren’t 100% correct. They have their limitations

In general, it’s not difficult to get the continent correct (e.g. European or Asian). Ancestry assignments also tend to be more accurate for populations that are well-studied, like European populations. 

In order for your ancestry to be correctly assigned, your ancestors needs to be represented in the database the company is using as a reference. They can’t figure out your ancestor is from Malta if they don’t have someone from Malta to compare to!

Blood chimera

– A curious adult from the US

June 19, 2018

If you are familiar with Greek mythology, you may recall the story of the chimera. It was a beast with the heads of both a lion and a goat, and a serpent in the place of its tail.

The original chimera
(Image from Flickr)


  – A curious adult from the US

June 4, 2018

Blood type is one of the key examples of genetic inheritance that we learn about in school. And in the vast majority of cases, blood type follows the rules of inheritance.

(Check out this post for more on the basics of the blood type inheritance!)

But as with all rules, there are sometimes exceptions! Cis-AB is one of them.

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Genetics of weight

 – An undergraduate from Denmark
May 22, 2018
Everyone knows that person who can eat whatever they want, whenever they want, without gaining an ounce. Maybe you are that (lucky) person. Or, perhaps, you are the type of person who counts every calorie, exercises, and still has trouble buttoning their pants in the morning. 
If your weight was 80% controlled by your genetics, it would be a lot harder to lose weight, right? Imagine this - you are trying to swim across a river to the other side:

Hair texture can change

- A middle school student from New Zealand

May 22, 2018

It’s possible that your hair could change as you get older. But it also might not! Let’s look first at why you have wavy hair, and what causes different hair textures.

Hair color can change

- A middle school student from the US

May 22, 2018

Hair and eye color are mostly determined by our genes. But it’s not just by the genes we have, but also by whether those genes are turned on or turned off. And since genes can turn on and off throughout our lives, this means your hair color can change!

The most important genes here are ones that make pigment, which is what gives hair its color.

The name of this pigment is melanin. It’s the same pigment that gives skin its color!

What happens when we age?

When we age our hair eventually turns gray and sometimes white. This occurs because our melanocytes (the cells that make melanin) wear out.

When melanocytes wear out, they aren’t as good at passing the pigment on to the cells that make hair. If this pigment isn’t passed on correctly, it doesn’t get included in the new hair. A hair that gets only a little pigment is gray, while a hair that doesn’t get any pigment is white.

Three equally represented phenotypes

This is for creative writing, so feel free to take any liberties in assuming the theoretical world's other aspects!

- A high school student from Texas

May 7, 2018


In a dominance series, version A of the gene is dominant to version B, which is in turn dominant to version C. We can represent this as A > B > C.

For our unicorns, average horns are dominant to big horns. Big horns are dominant to curved horns. Finally, curved horns are recessive, completing our dominance series A > B > C.

When we have three alleles, we have six possible genotypes. For our unicorns, they are as follows: