Many of these present it, not as an exclusive mode of reproduction, but alternately, with modalities of the miscegenation type. It also occurs in unicellular organisms, mainly protozoa, and unicellular algae.
- It can be defined in three ways, each accepted by different authors.
- Reproduction in which there is syngamy (fusion of gametes)
- Reproduction involving a process of meiosis (formation of haploid gametes)
- Reproduction involves a process of genetic recombination (offspring different from the parent)
Classification
The morphological and functional characteristics of the gametes allow us to differentiate between two forms of miscegenation reproduction: isogamic (type of miscegenation reproduction in which morphologically equal gametes are involved, hereditary transmission is through the mother) and anisogamic.
Isogamic miscegenation reproduction is seen in some algae, lower fungi, and protozoa. In this type of reproduction, the gametes have the same size, identical external shape, and the same physiology.
For this reason, it is not possible to call them male and female gametes, so the symbols + and – are used depending on their behavior.
Anisogamic or heterogametic miscegenation reproduction is the most frequent and is used by most multicellular organisms. In it, the gametes differ both morphologically and physiologically.
One of them is tiny and mobile, receiving the name of the male gamete or microgamete, while the other is large and sedentary and is called the female gamete or macrogamete.
Currently, with the new nomenclature, the microgamete is known as sperm, and the macrogamete, ovum.
Disadvantages of miscegenation reproduction
1. Below 50% of the people are competent of gestation.
Miscegenation reproduction enables a majority of females of child-bearing age to participate in gestation with this method.
Males do not commonly bear their young, although nature does have some instances where that option is possible.
People who show traits of both genders (or no gender) may not have the capability of participating in this part of the reproductive process.
That means there is a substantial risk to the survival of the species if one or the other sexes is in limited supply.
“The reproduction of mankind is a great marvel and mystery,” said Martin Luther King, Jr. “Had God consulted me in the matter, I should have advised him to continue the generation of the species by fashioning them out of clay.”
2. It compels each gender to find a mate.
Miscegenation reproduction enables a parent to have a child when the time is right for that process to occur. Sexual reproduction compels the finding of a mate.
If one is not found, then it is not possible to produce offspring. Humans work around this problem by creating genetic donation banks where single parents can seek to have a child, but it still requires the use of a surrogate or donated gamete to create the offspring.
Parthenogenesis occurs in nature quite often, encompassing complex animals like sharks and lizards. We also know that, with aid, stem cells from female donors can be induced to grow into sperm cells.
3. External influences can infer offspring viability.
Because miscegenation reproduction occurs instantly with a direct genetic transfer, there is a lower risk that the pregnancy will not be viable.
There are outside factors that can impact the processes of gestation with miscegenation reproduction so that healthy offspring can still develop undesirable changes to their genetic profile.
Mothers who drink alcohol during their pregnancy, continue to smoke, or fail to consume enough folic acid can make their otherwise healthy children develop physical or mental disabilities that could influence their entire life.
About 3,000 newborns every year have neural tube birth defects that are directly associated with a lack of folic acid each year.
4. Miscegenation reproduction can transport diseases to another individual.
Miscegenationally transmitted diseases have a serious impact on the reproductive health of any species.
More than 1 million new STIs are acquired each day around the world in the human population.
There are over 370 million new infections of four common infections: trichomoniasis, syphilis, gonorrhea, and chlamydia. About 500 million people have an HSV genital infection, while 290 million women have an HPV infection.
The problem with STIs is that several of them have zero symptoms. If a flare-up does occur, then the undesirable side effects might not be comprehended as an STI.
In 2016, there were almost 1 million women infected with syphilis during their pregnancy, resulting in about 350,000 adverse birth outcomes – including 200,000 newborn deaths or stillbirths.
5. This option for reproduction is not safeguarded.
Associates who are trying to have a child may say that they’re having fun with the process because of the benefits of miscegenation reproduction, but it is also thoughtful of this disadvantage.
You can do everything correctly, even at the optimal time to create a pregnancy, and not have the result that you want.
People and animals can sometimes choose infertile mates, limiting their chances to have offspring. The gametes may not fuse either.