How does a new mutation evolve and manage to to find a mate?

Question

While I believe in evolution, I need someone to explain to me how, when a newly mutated species or subspecies emerges, such as the celebrated "LUCY," who would they have to mate with in order to sustain this newly developed line? I take the case of the modern Homo sapien with 23 pairs of chromosomes, all of which I would presume would have to match up with another pair from a prospective mate in order for miosis to occur. Since both chimpanzees and gorillas have 24 pairs, I tend to expect that our common ancestor and our direct ancestral line, would also have the same. In any case, a lone mutant with a differing genetic configuration would have a very small chance of survival, let alone finding a mate to reproduce with. Horses and donkeys can mate, and even reproduce, but their offspring are not viably fertile. When such radical changes happen genetically through mutation how does a new linage manage to find a matching pair of viable genes?

Answer 1

I think I have the answer.

First, Lucy was probably part of a small band/tribe of inbred individuals which did not establish fixed pairings. Mutations, when they happen, are usually heterozygotic, but inbreeding brings them out (homozygosis) quickly.

Second, the difference in chromosome number between humans and apes comes from the fusion of two simian chromosomes: such events occur in humans to the present day as well (the most common is present in 0,1% of individuals) and the modality of meiosis is well known. Roughly, these individuals, *when mating with a normal individual*, have 50% chance of having an abnormal child, 25% of having a normal child and 25% of having a normal child who is a carrier of the translocation. In the small group, there is a transient stage of reduced fertility, followed by a return to normality once one or the other asset have become the norm.

Check this page for details (it also has the human 2 chromosome):

http://www.cbs.dtu.dk/staff/dave/roanoke...

So, Lucy could have mated pretty much with whoever made her get in the mood.

Answer 2

A new mutation is 99.9% genetically identical to all of the other members of its species, however, it has one new feature which makes it unique, and often times stronger, healthier or sexier, so it gets more chances to mate!

An example in humans, would be Blood Type "B", which arose about 10,000 years ago, after we started to domesticate hoofed animals. When we started to drink their milk, supplementally, when clean water was unavailable, one day, a baby was born with a new Blood Type, whose constitution was more compatible with digesting animal lactose.

Today, 11% of the world population (Nearly 700 Million) have Blood Type "B"...

Answer 3

First, you don't ever get a new species with the birth of one creature. "Lucy," to use your example, wasn't the 'first," and likely didn't look much different from her parents, grand parents and great grandparents. The problem you present simply doesn't happen.

Look around at today's population. There's a great variation in it.  Those individuals that  have traits that let them do better have a better chance of producing offspring. These offspring may or may not have the traits. Evolution isn't purposeful and directed to a specific goal.

Consider today's style of dress. Then compare it to that of 200 years ago. Researching, you can track how clothing changed over time. What you don't see is today's clothing suddenly appearing among hoop skirts or beaver fur top hats. That's the same with species. You don't see modern man appear suddenly among the Australopithecus.

Mostly likely small populations will have become isolated and hothouse evolution would occur. However the concept of one man and one woman going on to populate a planet doesn't work. If a species falls below a critical number, it will go extinct.

Evolution deals in millions of years. Think of it as watching a rock erode. You'd see little, if any, change in your lifetime. Over centuries, however, erosion would be apparent.

Answer 4

What you're describing is called the Hopeful Monster - a misunderstanding or misapplication of evolutionary theory.

Individuals do not evolve, populations do. Lucy was not the first of her kind, she belonged to a population of similar creatures who could all interbreed. The fossil remains of her body was merely our first record of her species; she wasn't alone.

Evolution proceeds by genetic mutations - small, usually unnoticeable changes in an organisms makeup - not mutations that create X-Men style mutants. Beneficial mutant genes give one individual an edge over their peers by allowing a small advantage - more disease resistance, cold-hardiness, more efficient enzymes of some sort, etc. The mutation does not have to be radical to confer an advantage. With that slight advantage, these individuals tend to survive and reproduce better than others. Their beneficial genes are passed on to more offspring and eventually become fixed in an entire population.

Evolution is defined as a change in gene frequency in a population over time. Given enough time and genetic mutation, a population that is reproductively isolated from others can accumulate enough differences to become quite different from their parent population.

Edit

We don't know everything there is to know about human evolution but this does not falsify evolution just as our inability to reconcile quantum theory and the theory of relativity does not mean gravity is an illusion. What we do know is that genetics is a very messy affair and the simplified "rules" talked about in most biology texts are much more fluid than you would think. Mechanisms have been described that can account for chromosomal changes (fission, fusion, and polyploidy) even though the details for the rise of Homo are incomplete.

http://www.talkorigins.org/origins/postm...

Because the genes can still align, a change in chromosome number does not prevent reproduction. Thus, hybridization is possible among incipient species with chromosomal rearrangements, although a lack of fitness is usually assumed. In other words change in chromosome number does not necessarily mean speciation. And, by the way, not all humans have exactly 23 chromosomes.

This obviously is an area that spurs a great deal of research. The literature is voluminous. Here's just a few samples:

Genomic Structure and Evolution of the Ancestral Chromosome Fusion Site in 2q13-2q14.1 and Paralogous Regions on Other Human Chromosomes

http://www.genome.org/cgi/content/full/1...

Testing the Chromosomal Speciation Hypothesis for Humans and Chimpanzees

http://www.genome.org/cgi/reprint/14/5/8...

The origin of man: a chromosomal pictorial legacy

JJ Yunis and O Prakash

http://www.sciencemag.org/cgi/content/ab...

http://www.indiana.edu/~ensiweb/lessons/...

This paper has a picture of all the chromosomes of man, chimpanzees, gorillas, and orangutans with each pair of chromosomes lined up next to each other and showing the 1000 band stage with all the sections labeled. Just by examining the picture you can clearly see that the chromosomes are remarkably similar. The differences are equally revealing as a vast majority are simple inversions of sections of chromosomes. Chromosome #2 of humans is shown next to two chimpanzee (and gorilla and orangutan) chromosomes since the human chromosome #2 is twice as long as the chimpanzee (and the other two as well), yet all the bands match up showing that the one less human chromosome is merely the result of the fusion of two chimp chromosomes.

Answer 5

the ability of creatures to reproduce is based on the genetic similarity between them, a few mutations here or there aren't usually enough to cause problems.

And there are instances in which groups of a species are separated from the original population, with this situation the groups are sharing genes(by reproduction) within their own groups but sometimes sharing genes across groups is impossable or not a vary often event. in this situation one group may have unique circumstances that are different from other groups, natural selection leads the groups away for the origional form, and once the differences add up reproduction is impossable and its considered a new species.

in plants, because of how some reproduce, it's entirely possible, and observable that they will take in the genetic information from another species during reproduction, and sense some can reproduce asexually if they cant find a set of genes to mate with, it is considered an instant species because there is no need for a mate in that case.

Answer 6

I'm sure there is a better answer than this...how about litters with all the genetics the same.  

identical twins?

I'm thinking that evolution is more progression and less mutation than you presume.