Reproduction and Mating Behaviors in Lizards and Birds
Exploring the fascinating world of asexual reproduction, this overview delves into the behaviors of lizards like the New Mexico whiptail, the adaptation of parthenogenetic species such as the Caucasian rock lizards to harsh environments, and the rare instances of parthenogenesis in birds. It also touches on the challenges of mammalian parthenogenesis and the potential medical applications of human parthenogenetic stem cells.
See moreAsexual Reproduction and Mating Behaviors in Lizards
Some lizard species reproduce asexually, a process where offspring are produced without fertilization by a male. Interestingly, certain asexual species, such as the New Mexico whiptail lizard, still engage in mating behaviors. These behaviors are not for reproduction but are believed to stimulate ovulation and increase fertility. During these interactions, one lizard assumes a role similar to that of a male and mounts the other, which is hormonally influenced. The lizard that has just laid eggs will have higher levels of progesterone, which is associated with male-like behavior, while the one about to lay eggs has higher estrogen levels, prompting the female role. These pseudo-sexual behaviors may enhance reproductive success, as lizards that engage in them tend to have higher egg production than those that do not.Geographic Parthenogenesis in Lizard Populations
Geographic parthenogenesis refers to the distribution pattern where asexual species are found in environments that are less hospitable to their sexually reproducing relatives. This is exemplified by certain parthenogenetic lizards, such as the Caucasian rock lizards of the genus Darevskia. These lizards, which reproduce through parthenogenesis, are often found in high-altitude environments where their sexually reproducing ancestors are less successful. For instance, the parthenogenetic lizard Darevskia dahli has a wider ecological range than its sexually reproducing progenitors and has colonized areas of the Central Lesser Caucasus. This expansion suggests that parthenogenetic lizards may have certain advantages over their sexually reproducing counterparts in specific environments, potentially leading to competitive exclusion and a reduction in the range of the parental species.Parthenogenesis in Birds and Its Limitations
Parthenogenesis in birds is a rare occurrence and has been observed in a few domesticated species, including turkeys, chickens, and pigeons. In these cases, the unfertilized eggs usually do not hatch or the embryos do not develop properly. However, in turkeys, parthenogenesis can occasionally produce viable offspring, which often exhibit reduced fertility and other abnormalities. Selective breeding can increase the frequency of parthenogenetic offspring in these birds. A remarkable instance of avian parthenogenesis was documented in 2021 when two unfertilized eggs from California condors hatched at the San Diego Zoo. This event was notable because it occurred despite the presence of males, highlighting the potential for parthenogenesis even in species where sexual reproduction is the norm.Challenges and Advances in Mammalian Parthenogenesis
Mammalian parthenogenesis does not occur naturally and is challenging to achieve even in a laboratory setting due to genomic imprinting, where genes are expressed differently depending on their parent of origin. This often results in developmental issues. Nonetheless, scientific progress has been made, such as the production of a bi-maternal mouse in 2004 through the manipulation of imprinted genes, which resulted in offspring with extended lifespans. While these advances are significant, mammalian parthenogenesis is not considered a viable reproductive strategy due to the associated developmental problems. Instead, research is focused on the potential of parthenogenetic processes to create embryonic stem cells for therapeutic applications.Human Parthenogenesis: Myth, Reality, and Medical Potential
Human parthenogenesis has never been scientifically verified to result in a viable pregnancy and is more commonly found in mythology and religious narratives, such as the Christian doctrine of the Virgin Birth. However, there have been instances of partial parthenogenesis in humans leading to chimeric individuals, who possess a combination of fertilized and unfertilized cells. In medical research, parthenogenesis has been used to create human stem cells, which could be valuable for generating genetically compatible tissues for transplantation. Scientists have also developed human stem cell lines that are HLA homozygous through parthenogenesis, which could potentially provide tissue derivatives that are less likely to be rejected by the immune system, benefiting a broader range of patients.Want to create maps from your material?
Insert your material in few seconds you will have your Algor Card with maps, summaries, flashcards and quizzes.
Try Algor
Learn with Algor Education flashcards
Click on each Card to learn more about the topic
1
Some lizard species, like the ______ ______ lizard, reproduce without male fertilization but still show mating rituals.
Click to check the answer
2
In asexual lizards, the individual with higher ______ levels exhibits male-like behaviors, while the one with more ______ assumes the female role.
Click to check the answer
3
Example of parthenogenetic lizard in high-altitude environments
Click to check the answer
4
Advantages of parthenogenetic lizards in specific environments
Click to check the answer
5
Impact of parthenogenesis on sexually reproducing parental species
Click to check the answer
6
In 2021, two unfertilized eggs from ______ successfully hatched at the ______, an exceptional case of avian parthenogenesis.
Click to check the answer
7
While parthenogenesis in turkeys can sometimes lead to viable chicks, these are likely to have reduced ______ and other ______.
Click to check the answer
8
Natural occurrence of mammalian parthenogenesis
Click to check the answer
9
Bi-maternal mouse significance
Click to check the answer
10
Research focus post-parthenogenesis challenges
Click to check the answer
11
In humans, ______ has not been confirmed to cause a sustainable pregnancy and is often seen in myths, like the ______.
Click to check the answer
12
Medical research utilizes ______ to generate human stem cells for creating tissues suitable for ______.
Click to check the answer