They say siblings share about 50% of their DNA. Yet it is also said that bananas and humans share 50-60% of their genetic material. What exactly is each claim referring to?
In: Biology
Cars and trains are made of wheels, axles, chassis, glass, seats, engines. Trains have parts cars don’t and nice versa. They’re made of 50% similar basic building blocks.
2016 Honda Civics and 2020 Honda Civics both have 4 wheels, two axles, two front seats, very similar engines, same shape steering wheels. But there are differences in peripheral support, safety features, trim.
DNA is a set of basic building blocks. We’re similar to bananas because we’re living things. We’re made of organic cells. We reproduce. The mechanisms evolved to do those jobs are very very similar. Like wheels or axles.
Genes represent small variations on very similar strategies. The chain of Honda’s are different from each other, but compared to semi trucks, or Porsches, or go-karts, they’re almost identical and clearly related. Siblings are made of identical building blocks with similar strategies.
All living things are made of some similar building blocks, but they may have wildly different strategies.
Obviously this is the case if your brother is a banana.
Haha. Anyway.
DNA is the building block of life. Specific sequences and combinations of the molecules that DNA is made of carry the information for how each cell in an organism functions. Every living thing on earth, and some viruses, has DNA in the nucleus of each of its cells. There are some basic requirements that every organism needs in order for its cells to function correctly and divide. These basic bits of genetic code are what we have in common with bananas, mushrooms, MRSA bacteria, and platypuses.
Now, when it comes to members of the same species, it is possible to tell how closely related they are by the portion of genes that they have in common. This is actually around 25% for siblings with the same parents, since you get about half your genetic data from each parent. So while you’re around 50% genetically similar to your mom, and your brother is too, you and your brother might not have the same 50% of your genes in common.
In short, DNA and genes are not the same thing. Your DNA establishes that you are a human. The genes that decide what you will look like (and other traits) are made of DNA, and, since you received them from your parents, are similar to those of your family members. The more genes you have in common with a relative, the closer you are related. For most people the maximum genetic similarity to another person is about 50%, which would be a parent and child, but for identical twins it is 100%.
Allow me to offer an analogy:
Transformers 3 and Transformers 4 share about 50% of their footage with each other.
The DVD Transformers 3 comes on is injection molded plastic, and a high school chair is also 50% injection molded plastic.
The difference between these things is basically the difference between your statements.
Actually, given two random humans, they share 99.4% of their genome. While given a human and a banana, they share ~60%.
The 50% thing is actually short for: in those 0.6% of variation, sibling share 50%, this means only 0.3% of difference between them.
So in the end, sibling actually share 99.7% of their DNA.
Genes make up segment of dna.. segments of dna make up chromosome..
So you and you sibling come from same set of parents (assuming).. so the 2 half set of chromosome, one from each parent, is common.. the difference here would be which segments of dna from each chromosome set is dominant giving the variation between the siblings.
The similarity between banana and human genetics material could come from the common ancestor that we shared eons ago which allow for similar built when it comes to cellular structure
Lets say you have two cookbooks with 99% of the same recipes, just slightly different versions in some cases, separated into the same chapters. For each chapter, pick at random which parent book to copy it from. If you do this again, you have two sibling cookbooks with 50% identical chapters.
For a banana analogy, compare one of these cookbooks to another recipe book, this time with only about half the recipes the same, the rest are different, there are more chapters, and the recipes aren’t categorized the same way.
The first claim is false. The correct claim is that siblings share about 50% of their chromosomes.
On average 50% of your chromosomes are identical to those of your siblings. It could theoretically be anywhere from 0% to 100%, but it’s most likely to be close to 50%.
That means that on average 50% of your chromosomes are different from those of your siblings. But since you’re both humans, these non-identical chromosomes still contain mostly the same DNA with some small differences here and there, which means you share much more than 50% of your DNA with them.
Humans share damn near 100% of our dna with each other. That small amount we don’t is the novel information that makes each of us different. That 50% is referring to the novel information. The 60% for banana is saying 40% of the dna is novel between the two species. Not the best at explaining but hope this helps
When you hear a phrase like, ” the human and the banana share 50% of their DNA” what someone means is that a human and a banana have 50% homologous genes. This means for 50% of the genes in the human you can find a gene in the banana that shares a evolutionary origin. These genes are not identical in sequence. The sequences can be as little as 30% identical and still be considered the same gene.
Siblings will get their chromosomes from their parents so the genes will be 100% identical except for the slight chance of mutation. However, which chromosome each parent gives to the child is random so on average we say each sibling share 50% of their DNA. Look up meiosis for the details on this process.
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