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Fig. 3 | Genetics Selection Evolution

Fig. 3

From: The second highest chromosome count among vertebrates is observed in cultured sturgeon and is associated with genome plasticity

Fig. 3

Comparison of normal fertilization, retention of the second polar body, and dispermic fertilization of a tetraploid female (4n) by spermatozoa of hexaploid male (6n). a Normal fertilization of diploid (2n) oocyte by triploid (3n) spermatozoon. b Retention of the second polar body in meiosis II results in tetraploid (4n) unreduced oocytes. If such an oocyte is fertilized by a triploid (3n) spermatozoon, it results in heptaploidy (4n♀ + 3n♂ = 7n), which is the ploidy level observed in the seven individuals under study. c Dispermic fertilization results in an octaploid (8n) zygote. If a diploid (2n) oocyte is fertilized by two triploid (3n) spermatozoa from a hexaploid male (6n), it will lead to octaploidy (2n♀ + 3n♂ + 3n♂ = 8n)

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