Life Lines by Dr. Dolittle

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Tag Archive for ‘reproduction’

Long sperm, short sperm, fast sperm, slow sperm

I read an interesting review published in Physiology that examined how sperm from different species are especially evolved to help promote fertilization, which if successful, results in the creation of an offspring. It is simply amazing to think of the multitude of ways this process occurs in nature. Take marine invertebrates and fish for example. These animals release eggs and sperm into the water. In contrast, fertilization happens internally in […]

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Role of phoenixin-20 in regulating appetite and glucose metabolism

Phoenixin-20 is a small peptide that has been detected in mammals, birds, amphibians and fish. Studies have shown that it can modify reproductive processes in female mammals and fish. In addition, it has been shown in mammalian studies to act as a pain reducer and modulator of food intake. In a new study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, researchers explored whether phoenixin-20 has […]

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What do nematodes and humans have in common?

Orthologs are genes present in different species that evolved from a common ancestor. While studies have shown the existence of orthologous genes and proteins in C elegans that are associated with diseases in humans, a new study published in Physiological Genomics examined this question as it relates to reproduction. In the new study, researchers identified a whopping 504 genes in C elegans that have yet to be associated with reproduction in humans whereas […]

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First known case of zebra shark switching to asexual reproduction

The story begins in 1999 when Leonie, a zebra shark (aka a leopard shark in Australia), was captured from the wild. In 2006 she was transferred to Reef HQ Aquarium in Queensland, Australia where she met her mate. By 2008, she had started laying eggs and the pair had multiple litters of offspring through sexual reproduction. After her mate was removed from the tank to prevent further breeding, she has shared the tank with […]

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The cost of male pheromones

A new study conducted by researchers at Northwestern University examined the costs of reproduction in roundworms, otherwise known as C. elegans. They discovered that male roundworms can send two kinds of pheromones that prime females for reproduction. One type of pheromone they studied sparks the onset of puberty in young female worms while the other prolongs fertility in aging females.  The problem is that these changes come at a cost as it shortens the lifespan of […]

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100-year old manuscript talks about the sexual “crimes” of penguins

According to the report on the Discover Magazine website, George Levick, a surgeon and zoologist, went on an Antarctic expedition with Captain Robert Scott (the Terra Nova Expedition) where he spent time observing and documenting the largest colony of Adélie penguins at Cape Adare (image above). Following his trip he published a story about the penguins for the general public as well as a scientific account. It was in this second document that he wrote […]

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