Can Down's Syndrome people be classed as a different species of human?

Question

I'm not saying they're less than people or are worthless. This is a serious question and I can't often find a serious answer for these questions because people take such offense to this that they immediately brush it off because they don't like the question.

Why I ask this is because humans have 46 chromosomes, gorillas, and other great apes have 48 chromosomes, and Down's syndome people have 47. I'm NOT comparing them to apes, and I'm not removing their personhood. I'm just saying that maybe they are an offshoot of the major human species. Like an evolutionary branch. An unsuccesful mutation that wouldn't survive without care, but a mutation nonetheless.

Please answer this as a serious question, as I know I'm definitely going to get the "how can you say that?!" answers. Once again I'm not arguing against their personhood, just that they might be different enough to be a different type of human. A person who can give me a calm logical answer will get best answer.

Answer 1

That is actually a very insightful question and non something I've ever thought about. I understand you're thinking and don't believe there is a definitive answer to this question. As you've said Down's is due to a trisomy mutation. And thats the key, its a mutation. A 'species' of people with Down sydrome wouldn't naturally occur through evolution since a mutation is a 'spontanious change in the structure or arrangement of DNA'. Also if you think about it logically and applied a catch all mutation = different species where would we be! I certainly don't consider someone with albinoism a different species, nor someone with black skin. Also the definition of a species is 'two organisms that come together to produce viable/fertile offpspring'. I know my answer isn't definitive but I think I'll have to go with mutation, rather than speciation.

Answer 2

Down Syndrome Animals

Answer 3

Definitely not because they don't have a COMMON ANCESTOR.



In fact, almost all cases of individuals with Down syndrome descend from normal parents and are not related.



The chromosomal anomaly can, in theory, be inherited. But since individuals with Down syndrome are almost always sterile this practically never happens. Mutations can lead to a new species only if they can be inherited.



There are a lot of slightly different definitions of species but (maybe with the exception of creationist ones) they all agree that, to be included in the same species, individuals must share a common ancestor.

Answer 4

A simple way to define whether two organisms are the same species is by whether they can breed and produce a fertile (able to reproduce) offspring.



About 30% of females with Down Syndrome are fertile, meaning they can have children with non-Down Syndrome men. Those children have a 50% chance of having Down Syndrome (assuming the man is not a carrier) and a 50% chance of not. No men with Down Syndrome have been recorded fathering a child, either with a Down Syndrome or non-Down Syndrome woman.



Given that, I'd say that people with Down Syndrome are not a separate species - it affects, among other things, the *ability* to reproduce, but it doesn't mean they *can't* reproduce with "normal" humans. And certainly, since the men appear to be infertile, they're not reproducing with each other.



Remember, biology is very much a continuous thing, and species are our attempt to divide that continuum into discrete boxes. It doesn't always work well!



I hope that helps!

Answer 5

Well, the straight-up answer is that Down's Syndrome is considered a variation in humans rather than a separate class of humans at all.



More scientifically, they can't be a different species. The definition of a species is a group of animals which can procreate with each other but not create fertile offspring with others. People with Down's Syndrome don't meet those requirements.

Answer 6

People suffering with Down's syndrome cannot be classified as a different species. They have 47 chromosomes due to non disjunction. Down syndrome is not the only genetic disease which causes an abnormal amount of chromosomes to be passed.

This does not make them a new species, this just makes them very unlucky to end up with that defect. To consider a person with down syndrome as a new species is like saying everyone that is born with dimples or red hair or blue eyes or 6 fingers are a new species of their own.



Hope that answered your question.

Answer 7

to tricky dicky trisomy is not a mutation is caused by a process of non disjunction.



Non-disjuction is the failure of chromosome pairs to separate properly during meiosis. This could arise from a failure of homologous chromosomes to separate in meiosis I, or the failure of sister chromatids to separate during meiosis II or mitosis. The result of this error is a cell with an imbalance of chromosomes. Such a cell is said to be aneuploid. Loss of a single chromosome (2n-1), in which the daughter cell(s) with the defect will have one chromosome missing from one of its pairs, is referred to as a monosomy. Gaining a single chromosome, in which the daughter cell(s) with the defect will have one chromosome in addition to its pairs is referred to as a trisomy.



Also don't use the term species to loosely. More chromosomes does not mean stupider flies only have 4. Persons with down are humans and not different species it's ludicrous to even say that. the definition for species is: . A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. Persons with down can interbreed with you only because they have extra chromosome the changes are the child will be with down 2.



So to recap Down is not a MUTATION but caused by nondisjuction (x-men screwed the term mutation).You have some non-disjuncted sperm of eggcells in you even now. Down people are not of a different species because they can produce fertile offspring.





Additional Details



Yea saying that non-disjunction can be caused by mutation can confuse you so i deleted that part. That mutation was aimed at the parents that might have higher levels of non-disjuction and not the person with Down. Non disjunction is a normal process having to do with the mechanics of meiosis. Mutation is term that is used when DNA gets altered. In people with down their DNA is not altered they just have one chromosome. So please dont say people with down are mutants. And they are human because they have the same DNA basically the same physical appearance an can interbreed with humans who are not inflicted by trisomy. You can not mate with a gorrilla for instance and expect a baby making them a different species.

Answer 8

No.

1. They're not a population.

2. Fertility is so low that they would not reproduce at a replacement rate.