Laudean/Genetics
Gender Chromosomes
The Laudeans, like the Vissians, are a tri-gendered species. Unlike the Vissians, the Laudeans do not have a third sex chromosome. Instead they utilize an extra pair of male/female chromosomes. Like humans, they have two sex chromosomes (X and Y). Each Laudean has two pairs of these chromosomes however: XXXX for women, XXYY for men, and XXYX or XXXY for lomales.
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Chromosome Count
Laudeans, like most other species known to the Federation, have 46 chromosomes. Because they have 2 pairs of sex chromosomes this means they only have 21 pairs of autosomes. Therefore, they shouldn’t be able to crossbreed with other species, but the presence of half Laudean/half Romulan children living in Lokesh Cities homeless area prove otherwise. There are also a few half species children elsewhere. The explanation of this is unknown. It is possible that one of the pairs of sex chromosomes does double duty as an autosome pair.
Cross-species Breeding
It appears that the lomale requirement is tied to the female Laudeans reproductive cycle. This is due to the fact that a Laudean male may breed with a non-Laudean female without the need for a lomale, but the reverse is not true. This may be due to the fact that the females egg cell actually has a double cell membrane. Where other species only have one phospholipid bilayer in their cell membranes, Laudeans only have two. It appears that the lomale enzyme breaks down the outer layer, allowing a sperm cell to fertilize the egg. Without a double layer, the lomales enzyme is not needed for fertilization.
Since there is no unique third gender chromosome, there are no half breed lomales.