See the link below.

In snakes the females are WZ and the males are ZZ. So the father always gives Z and daughters are caused when the mother gives W and sons when she gives Z. So the mother determines the gender on what should in theory be the long term observed 50/50 split.

However, the 16 females in a row works out to 1 in 65,536. The example of 45 females in a row 1 in 35 trillion. So, something is up here that looks to be a considerable deviation from the expected.

Where there many eggs that failed to hatch in either case? Maybe these males are homozygous for a "son killer" version of the Z chromosome (opposite of the article). Of course that bags the question of how are the fathers alive. Maybe it's only fatal when paired with a normal Z. But where the first homozygous "son killer" Z male came from would be a good question. Maybe there is some regional variation of the Z of these males that just isn’t compatible with the more common Z seen in the mothers.
ZW Species

[ Hide Replies ]

• 0.16 ----What are the odds? - tomsiegrist, Mon Aug 28 12:45:59 2006
• Technically speaking..... - JP, Mon Aug 28 12:52:44 2006
• RE: Technically speaking..... - cid143ti, Mon Aug 28 13:12:40 2006
• RE: Technically speaking..... - toshamc, Mon Aug 28 13:25:08 2006
• It's the male...np - bpconnection, Mon Aug 28 15:24:57 2006
• Pretty sure it's the female - RandyRemington, Tue Aug 29 00:43:54 2006
• Randy...another possibility - rwoodyer, Tue Aug 29 13:03:29 2006
• Lots of possibilities - RandyRemington, Tue Aug 29 19:25:08 2006
• Ummmmmmmmmmmmmmm...... - jeff favelle, Mon Aug 28 19:01:25 2006
• RE: 0.16 ----What are the odds? - dwherp, Mon Aug 28 13:45:58 2006
• that is what I was hoping.... - tomsiegrist, Mon Aug 28 15:00:36 2006
• RE: that is what I was hoping.... - Herpout, Mon Aug 28 20:37:38 2006
• temps during incubation.... - tomsiegrist, Mon Aug 28 23:17:01 2006