Updated: Dec. 30 (2023)
Lanceolate Hairless
Lanceolate Hairless, lah/lah
Two copies of the recessive Lanceolate Hairless
Chromosome: 18
RVG description:
The lah/lah rats are born naked with pink, wrinkled skin and are distinguishable from normal rats at birth by their relatively small size. The vibrissae and first hair coat appear around day 5, with the skin developing a stubble-like dark, gray hue. Hair growth then progresses from the head to tail region with the rat developing a full coat of pelage hair around 2 weeks. At this stage they are still distinguishable from brown rats by size and coloration. Hair loss begins shortly afterward and culminates around 4 weeks when the rats are completely bald. Hair regrowth starts again a few days later, following an approximately 29-day cycle of external growth and loss generally from head to tail with ventral to dorsal change as well. In some animals the region around the eyes(sometimes extending in a line to the neck) is spared in early cycles. With each subsequent growth cycle hair regrowth was less significant and it became increas-ngly patchy and ‘‘stubbly.’’ Almost complete pelage hair loss occurred by 18 months, although in these rats the skin still underwent cyclical changes alternating between a dark gray and pink/yellow color, indicating that follicle remnants were still cycling. Vibrissa follicles continued to produce whisker fibers throughout, but these were sometimes abnormally shaped and grew in unusual directions.
Sources:
Two copies of the recessive Lanceolate Hairless
Chromosome: 18
RVG description:
The lah/lah rats are born naked with pink, wrinkled skin and are distinguishable from normal rats at birth by their relatively small size. The vibrissae and first hair coat appear around day 5, with the skin developing a stubble-like dark, gray hue. Hair growth then progresses from the head to tail region with the rat developing a full coat of pelage hair around 2 weeks. At this stage they are still distinguishable from brown rats by size and coloration. Hair loss begins shortly afterward and culminates around 4 weeks when the rats are completely bald. Hair regrowth starts again a few days later, following an approximately 29-day cycle of external growth and loss generally from head to tail with ventral to dorsal change as well. In some animals the region around the eyes(sometimes extending in a line to the neck) is spared in early cycles. With each subsequent growth cycle hair regrowth was less significant and it became increas-ngly patchy and ‘‘stubbly.’’ Almost complete pelage hair loss occurred by 18 months, although in these rats the skin still underwent cyclical changes alternating between a dark gray and pink/yellow color, indicating that follicle remnants were still cycling. Vibrissa follicles continued to produce whisker fibers throughout, but these were sometimes abnormally shaped and grew in unusual directions.
Sources: