Evolutionary trends in sperm structure

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

“…The head morphology of Siberian sturgeon sperm is elongated, cylindrical and radially symmetrical, as found in other sturgeon species (Ginsburg, 1968, 1977; Cherr and Clark, 1984; DiLauro et al, 1998, 1999, 2000, 2001), and the tail is differentiated with a narrow part at the end (Figure 1). These results support the suggestion of many researchers (Baccetti et al, 1984; Jamieson, 1991; DiLauro et al, 2001) that spermatozoan ultrastructure is of taxonomic use and that the spermatozoa of sturgeon species are primitive in their general organization, because the cells have an almost radial symmetry, are discharged directly into the water and their duration of motility is long (Anderson and Personne, 1975; Baccetti, 1986). Comparisons of morphological parameters in different species of sturgeon (Table 4 and Figure 7) reveal interspecies variation.…”

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

“…The head morphology of Siberian sturgeon sperm is elongated, cylindrical and radially symmetrical, as found in other sturgeon species (Ginsburg, 1968, 1977; Cherr and Clark, 1984; DiLauro et al, 1998, 1999, 2000, 2001), and the tail is differentiated with a narrow part at the end (Figure 1). These results support the suggestion of many researchers (Baccetti et al, 1984; Jamieson, 1991; DiLauro et al, 2001) that spermatozoan ultrastructure is of taxonomic use and that the spermatozoa of sturgeon species are primitive in their general organization, because the cells have an almost radial symmetry, are discharged directly into the water and their duration of motility is long (Anderson and Personne, 1975; Baccetti, 1986). Comparisons of morphological parameters in different species of sturgeon (Table 4 and Figure 7) reveal interspecies variation.…”

Recent Origins of Sperm Genes in Drosophila

“…The absence of rapid evolution across the DmSP is perhaps not surprising as many integral sperm proteins are involved in essential and oftentimes ubiquitous functions, such as metabolism and energetics. This finding highlights the central role of sperm in sexual reproduction and likely reflects the ancient evolutionary history of sperm (Baccetti 1982(Baccetti , 1986. In this study, we have utilized an alternative approach to specifically determine if gene creation is a mechanism driving the evolution of sperm form and function and demonstrate that Drosophila sperm has, in fact, been impacted by the recent origination and diversification of novel sperm genes.…”

Comparative ultrastructure of the spermatogenesis of three species of Poecilosclerida (Porifera, Demospongiae)

“…Historically, the 327 presence of acrosome in Porifera brought the following question: is the acrosome a primitive 328 organelle that disappeared during evolution in most of the orders, or a new organelle 329 secondarily evolved in a few species? (Baccetti 1986). In the past, thesperm ultrastructure in 330 sponges supported the hypothesis presented by Afzelius(1972) that primitive spermatozoa may 331 have arisen twice, once in Porifera and another inall other metazoans.…”

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

“…The head morphology of Siberian sturgeon sperm is elongated, cylindrical and radially symmetrical, as found in other sturgeon species (Ginsburg, 1968, 1977; Cherr and Clark, 1984; DiLauro et al, 1998, 1999, 2000, 2001), and the tail is differentiated with a narrow part at the end (Figure 1). These results support the suggestion of many researchers (Baccetti et al, 1984; Jamieson, 1991; DiLauro et al, 2001) that spermatozoan ultrastructure is of taxonomic use and that the spermatozoa of sturgeon species are primitive in their general organization, because the cells have an almost radial symmetry, are discharged directly into the water and their duration of motility is long (Anderson and Personne, 1975; Baccetti, 1986). Comparisons of morphological parameters in different species of sturgeon (Table 4 and Figure 7) reveal interspecies variation.…”

Recent Origins of Sperm Genes in Drosophila

“…The absence of rapid evolution across the DmSP is perhaps not surprising as many integral sperm proteins are involved in essential and oftentimes ubiquitous functions, such as metabolism and energetics. This finding highlights the central role of sperm in sexual reproduction and likely reflects the ancient evolutionary history of sperm (Baccetti 1982(Baccetti , 1986. In this study, we have utilized an alternative approach to specifically determine if gene creation is a mechanism driving the evolution of sperm form and function and demonstrate that Drosophila sperm has, in fact, been impacted by the recent origination and diversification of novel sperm genes.…”

Comparative ultrastructure of the spermatogenesis of three species of Poecilosclerida (Porifera, Demospongiae)

“…Historically, the 327 presence of acrosome in Porifera brought the following question: is the acrosome a primitive 328 organelle that disappeared during evolution in most of the orders, or a new organelle 329 secondarily evolved in a few species? (Baccetti 1986). In the past, thesperm ultrastructure in 330 sponges supported the hypothesis presented by Afzelius(1972) that primitive spermatozoa may 331 have arisen twice, once in Porifera and another inall other metazoans.…”

Morphology and ultrastructure of Siberian sturgeon (Acipenser baerii) spermatozoa using scanning and transmission electron microscopy

“…The head morphology of Siberian sturgeon sperm is elongated, cylindrical and radially symmetrical, as found in other sturgeon species (Ginsburg, 1968, 1977; Cherr and Clark, 1984; DiLauro et al, 1998, 1999, 2000, 2001), and the tail is differentiated with a narrow part at the end (Figure 1). These results support the suggestion of many researchers (Baccetti et al, 1984; Jamieson, 1991; DiLauro et al, 2001) that spermatozoan ultrastructure is of taxonomic use and that the spermatozoa of sturgeon species are primitive in their general organization, because the cells have an almost radial symmetry, are discharged directly into the water and their duration of motility is long (Anderson and Personne, 1975; Baccetti, 1986). Comparisons of morphological parameters in different species of sturgeon (Table 4 and Figure 7) reveal interspecies variation.…”

Recent Origins of Sperm Genes in Drosophila

“…The absence of rapid evolution across the DmSP is perhaps not surprising as many integral sperm proteins are involved in essential and oftentimes ubiquitous functions, such as metabolism and energetics. This finding highlights the central role of sperm in sexual reproduction and likely reflects the ancient evolutionary history of sperm (Baccetti 1982(Baccetti , 1986. In this study, we have utilized an alternative approach to specifically determine if gene creation is a mechanism driving the evolution of sperm form and function and demonstrate that Drosophila sperm has, in fact, been impacted by the recent origination and diversification of novel sperm genes.…”

Comparative ultrastructure of the spermatogenesis of three species of Poecilosclerida (Porifera, Demospongiae)

“…Historically, the 327 presence of acrosome in Porifera brought the following question: is the acrosome a primitive 328 organelle that disappeared during evolution in most of the orders, or a new organelle 329 secondarily evolved in a few species? (Baccetti 1986). In the past, thesperm ultrastructure in 330 sponges supported the hypothesis presented by Afzelius(1972) that primitive spermatozoa may 331 have arisen twice, once in Porifera and another inall other metazoans.…”