10 Unusual (But Scientifically Sound) Methods of Reproduction

by Johan Tobias

Birds do it, bees do it, and even kleptogenic salamanders do it. No, it’s not fall in love, although maybe that’s part of it. It’s just reproducing. And while as humans we’re most familiar with the process of one male and one female sharing some genetic material so that a baby can be formed, not every living thing under the sun likes to multiply in the same fashion. Some continue their genetic line in ways that are almost unbelievable. 

10. Kleptogenesis Involves Stealing Genetic Material

Kleptogenesis does not involve stealing an early 90s gaming system, but it’s potentially just as cool. One species of salamanders exist solely as females so when it comes time to reproduce they have to be a little bit more creative than your average binary species. In the case of these little amphibians,the solution to their single sex conundrum comes in the form of theft. They steal sperm from males of other species in the same genus and decide for themselves how to use it. If that sounds baffling it’s because it is, but it’s been happening for millions of years, so just assume they know what they’re doing.

Salamander males will drop sperm packets that will then fertilize eggs from the females. Normally this gives you the kind of reproduction you’d expect, with a baby salamander that’s 50% of each parent. But for this one species, that’s not the case.

The females, and there are only females in this species, can collect multiple sperm packets and then apparently they have the ability to sort the genes they want to use. The result is that some of these salamanders have up to five different genomes in their cells. 

The mothers are able to discard whatever genetic material they don’t want from the males, and pass down a variety of genomes, as few or as many as they want, to their offspring. Some have been identified from species the salamanders don’t even descend from.

So, how does a salamander choose what genes to pass on? Good question. Scientists are still trying to figure that out.

9. Gynogenesis Uses Sperm But Not for Genetic Material

This method is kind of similar to kleptogenesis, but more restrictive. Essentially, animals that reproduce through gynogenesis need sperm to start the reproductive process, but not to finish it. So sperm needs to reach an egg and begin fertilization, but then the sperm and its genetic material is discarded and the offspring is made up solely of what the mother brings to the table.Think of it like the mother asking the would-be father to unlock the door to their apartment, but then she closes it in his face after and spends the night alone.

The key thing to remember about gynogenesis and what separates it from something like asexual reproduction and parthenogenesis when only one parent is needed is that gynogenesis does require a male’s involvement, just not his genetics. 

8. Hybridogenesis Occurs When One Half of a Hybrid’s Parents Genetics Are Combined with a Second Parent’s

The term “sexual parasitism” doesn’t sound entirely pleasant, but that’s how you can describe hybridogenesis, an extremely rare form of reproduction that can only occur with an already existing genetic hybrid. The mother has two different genetics from species A and species B. When it is time to reproduce, she will produce a gamete that may be genetically all A or all B, not a combination. That means when the egg is fertilized it will be 50% of the male and then 50% of only one half of the female’s genetics, meaning one genome will be entirely eliminated in reproduction.

Consider something like a mule. It’s a hybrid of a donkey and a horse. If a female mule were to mate with a horse, the mule’s gamete could be 100% horse and no donkey at all. Thus, when the male fertilizes the egg, the offspring will be 100% horse and the donkey genetics will be totally absent. 

Typically, this type of reproduction occurs in some species of frogs and a few fish as something like a mule is usually sterile. That said, a few mules have been bred over the years and some of their offspring seem to be genetically full horses. 

7. Sporogenesis is the Production of Spores to Reproduce

Have you ever wondered how a mushroom reproduces? Well, wonder no more because many fungal species take part in sporogenesis. In these and some plant and algae species, reproductive spores are formed that can remain dormant for a very long time. This is chiefly as a way of preserving the species during unfavorable living conditions. So if there was a drought, for instance, a fungus could create these spores and they could remain lifeless until drought conditions passed and then they could begin to grow. 

Under normal conditions, a fungus could reproduce sexually, but it may also release spores that are genetically identical to the parents, when it needs to. It can continue to do this until such time as traditional reproduction is an option again. 

6. Parthenogenesis Happens When an Unfertilized Egg Produces Offspring

Parthenogenesis is sort of like a surprise method of reproduction where an animal that normally reproduces sexually is able to produce an egg that isn’t fertilized but still gives rise to offspring, in this case genetically identical to the parent. It’s a favorite method of reproduction for marine tardigrades and some much more complex organisms will occasionally reproduce this way as well. In one case, a female shark that hadn’t been exposed to males for years gave birth to a baby that was a clone of the mother. 

Various arachnid species may reproduce through parthenogenesis but it has also been noted in reptiles, amphibians and birds as well. 

5. Fragmentation Is When a Severed Piece of an Organism Can Keep Growing

In terms of creepy reproduction methods, you’d be hard pressed to find anything that tops fragmentation. This is the kind of stuff that happens in horror movies. In simple terms, this happens when an organism gets damaged so badly it loses a piece of itself. That new piece doesn’t just wither and die like your hand would if it was accidentally lopped off, however. Instead, it grows into a whole new organism.

The fragment offspring will be a clone of the parent so that when it’s done, there will be two identical organisms, even though there was nothing close to sex involved in the forming of the second organism. 

It’s possible for fragmentation to be a natural form of reproduction but it’s just as likely to happen when an accident rips a limb off. Fortunately for those who find it unsettling, not a lot of creatures are able to do it. Most notably, this is how some starfish are able to reproduce, but there are some other species like earthworms that can pull it off as well. 

4. Budding Occurs When a Species Grows a New Clone That Pinches Itself Off of the Parent

Budding sounds fairly innocuous and not at all like a method of reproduction but it’s the name for the process organisms like hydras, jellyfish and yeast undergo when it’s time to produce a new round of life. 

The name refers to the fact that the parent organism will develop what looks like an actual bud, like you might see on a plant. The bud begins to form an exact copy of the parent organism until it is complete enough to separate fully from the parent and exist as a separate life form. The parent is left with a scar where the bud baby pulled away and became something new.

The new organism will be identical genetically to the parent but it will also be smaller because it’s still growing. Unlike something like binary fission, which we’ll see shortly, this process can be done with more complex, multicellular organisms. In a way it’s like what you might consider a typical pregnancy but it’s asexual and the offspring doesn’t develop inside the parent but on the parent until it matures enough to leave. 

In a species like the hydra, the buds form at a specific juncture between the stalk and gastric regions. If conditions are ideal, the hydra can produce a new version of itself every couple of days this way. 

3. Heterogony Occurs When a Species is Born Pregnant

If you’re the kind of person who likes to cut out the middleman and get right to the point, then heterogony is for you. Insects like aphids are able to reproduce in this fashion and it allows for the new generation to be born already pregnant with no need to worry about that time-consuming mating process. 

Aphids don’t lay eggs; they have live births and a single aphid is able to produce several perfect clones a day. This is how aphid infestations are so efficient, you really only need one to start an entire colony.

The insects have the ability to reproduce sexually if they want to, and will do this to add genetic diversity to ensure stronger offspring when the situation allows.

2. Binary Fission Involves Making an Exact Copy

Binary fission sounds very sci-fi and maybe a little dangerous but it’s actually one of the simplest forms of reproduction in nature. So simple, in fact, only simple life forms like various kinds of bacteria can do it because the rest of us are just far too complex to pull it off.

Found in simple single-celled organisms and a few other microscopic beasts, binary fission occurs when the DNA of the single cell begins to copy itself and essentially sticks all of the new material to the wall of the cell until it’s so full of new material the cell splits in two and now there are two completely identical cells and the long single-celled organism has become two. It made its own twin!

1. Plant Grafting Can Mix Numerous Species in One Place

Plant reproduction is obviously a little different from animal reproduction but for the most part we understand that one plant needs to be pollinated by another and at some point a seed forms and maybe a new plant grows as a result. More or less. But plants have a few extra tricks up their sleeves that allow them to thrive under the most unusual conditions and nothing is more bizarre than grafting.

Because so many plants are genetically similar, as in they come from the same family, botanists and horticulturists have discovered over the years that you can take a cutting from one plant and attach it to a different plant to produce something brand new. And, just like a human limb transplant, that cutting can heal in place and begin to grow. But unlike a limb transplant, this new branch can be so different that what you create is a fruit tree that now grows two different fruits. Or, if you really want to push the envelope, you can make what they call fruit salad trees.

Right now you can buy a tree that grows limes, mandarin oranges and pomelos. Or maybe one that grows peaches, nectarines, plums and other stone fruit. Word is you can get some that grow as many as 7 or 8 different strains of fruit on the same tree and they come in four main varieties including citrus, stone fruit, apple and nashi which grow Asian pears

See also  10 Unusual Genes And The Things They Do

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