Imprinted gene anomalies in sperm

• Tipo: Capítulo ou Parte de Livro
• Data: 2010

Autores

Marques, CJ (Autor) Outra; sousa, m (Autor) ICBAS

Livro

Título: Paternal Influences on Human Reproductive Success

Páginas: 27-37

ISBN: 9781139169349; 9781107024489

Indexação

Scopus - 2 Citações

Outras Informações

ID Authenticus: P-00A-7FM

DOI: 10.1017/9781139169349.005

Abstract (EN): Spermatogenesis is the process by which a spermatogonial stem cell gives rise to a spermatozoon [1]. It can be divided into three distinct phases. The first phase involves the proliferation of spermatogonia, maintaining their number by self-renewal but also giving rise to spermatocytes. The second phase involves the primary and secondary spermatocytes, which go through the process of reductional or meiotic divisions leading to the formation of haploid cells, the spermatids. The third phase concerns the spermatids, which go through a complex series of cytological transformations leading to the production of the spermatozoon (Figure 4.1). The entire process, from primary spermatocytes to spermatozoa, takes approximately 64 days in humans [2]. The undifferentiated germ cells, termed spermatogonia, start to divide mitotically at puberty, giving rise to a clone of cells. Additionally to mitosis, some differentiation occurs, giving rise to primary spermatocytes [3]. Two types of spermatogonia have been described in man: type A, divided into dark (stem) and pale (progenitor) varieties, which differ by nucleus chromatin staining, and type B spermatogonia. Type A and B spermatogonia can be distinguished by their morphology although this can be difficult since morphological characters alter through the life cycle of the cells. It is only during their long S phase and in G2 phase that they acquire their characteristic nuclear morphology [1]. Type A spermatogonia belong to the stem cell pool of spermatogenesis whereas type B represent the onset of germ cell development up to spermatids [4]. © Cambridge University Press 2013.

Idioma: Inglês

Tipo (Avaliação Docente): Científica