One of the questions we receive most frequently at Ancestrum is: “Why do my Ancestry results not match those of my parents or siblings?” Although our logic might indicate that the results should be practically the same, science and genetics say otherwise.
In this blog, we will delve into the fascinating world of genetic inheritance and explore the reasons behind the differences in Ancestry test results among close relatives.
What is Genetic Inheritance?
Genetic inheritance is the process by which the physical and biological traits of parents are passed on to their children. Genetic information is found in our chromosomes, which are structures in our cells that contain our genes. Genes can be understood as instructions for our body that determine characteristics such as the color of our eyes or the type of hair we have, among many others. Each person receives 50% of their genetic information from their mother and the other 50% from their father, which means that our traits are a combination of our parents’ traits.
Genetic Inheritance: Recessive and Dominant Alleles
When we talk about genetic inheritance, we often hear the terms “recessive alleles” and “dominant alleles.” An allele is a version of a gene that is located in a specific place on our chromosomes. Each of our parents transmits one allele of each gene to us, and it is the combination of these alleles that determines our physical and biological traits.
A dominant allele is one that is expressed when it is present in one of the two alleles of a gene. That is, if we inherit a dominant allele from one of our parents, this allele will be expressed and will affect our appearance or biological characteristics. An example of a dominant allele is the one that determines brown eye color, which is expressed over the recessive allele for blue.
On the other hand, a recessive allele is only expressed when it is present in both alleles of a gene, that is, when there is no dominant allele present. If we inherit two recessive alleles from both parents, this allele will be expressed and will affect our appearance or biological characteristics. An example of a recessive allele is the one that determines blue eye color, which is only expressed when there are two copies of this allele in an individual.
Variations in recessive and dominant alleles are what make us unique biologically and physically. For this reason, although we may find physical similarities with our siblings, we are not exactly the same, right? The same thing happens with ancestry inheritance.
What is Genetic Recombination?
Although we share many genes with our close relatives, the exact combination of alleles that we inherit from each parent is random, which can lead to significant differences. In addition, parents can also have recessive alleles that are not expressed in them but can be passed on to their children. These alleles can combine in unpredictable ways, which can lead to unexpected traits in offspring. This is known as genetic recombination.
A very clear example is when a brown-eyed father and mother have a blue-eyed child. How is this possible? If we take a look at the family tree on both sides, we will find an ancestor with blue eyes. For example, the great-great-grandmother of the father and the great-grandmother of the mother. This trait remained recessive in the parents but turned out to be dominant in the child.
Genetic recombination and ancestry
When we talk about ancestry, something similar happens. Due to recombination, although we inherit 50% of our DNA from each of our parents, the ancestry information that comes through that DNA may not exactly coincide 50/50 with that of our parents or with that of a sibling. Therefore, although biological siblings share the same family tree, their ancestry results could differ significantly.
The effects of genetic recombination can be more significant the more diverse recent ancestors are. For example, if maternal grandparents are from different ethnicities, your mother will have a random mixture of them. This leaves a more diverse set of genetic possibilities to be randomly passed down to her offspring as well 
What other factors influence inherited traits?
Another factor that causes variations in ancestry test results is the database being used. Many companies face the limitation that the majority of samples are focused on Europe and North America. For this reason, it is imperative that when choosing an ancestry test, we look for one that covers the greatest number of countries and regions in the world.
Ancestrum, the most complete Ancestry test on the Market
Ancestrum stands out as the most comprehensive genetic testing option for ancestry available worldwide, offering seven distinct types of studies, united into a single report. Unlike any other available test, it provides a diverse range of studies that enable you to discover your identity and trace the origins of your DNA. By choosing Ancestrum test, you will have access to a consolidated report that encompasses the following studies: Geographic Ancestry +2.000 regions, Ethnic ancestry: +300 ethnicities Worldwide, Historic Ancestry, Maternal Haplogroup, Paternal Haplogroup, Neanderthal DNA and Celebrity Matching.