Dainee Gibson Biology 440 Population Genetics T Gene Part of TBox Complex Important for anteriorposterior development Mutations in this gene influence tailtaillessness Brachyury in the T Gene ID: 249325
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The Long and Short of it: Mammalian Tail Genetics and Evolution
Dainee GibsonBiology 440: Population GeneticsSlide2
T Gene
Part of T-Box ComplexImportant for anterior-posterior developmentMutations
in this gene influence tail/taillessnessSlide3
Brachyury in the T Gene
Affects tail length and spinal cordResults in shortened tailAnury is complete taillessness—related to
Brachyury
Homozygous usually lethalSlide4
Manx Cats
Dominant
Manx Gene allele
Homozygous
lethal
Spinal
and colon
malformationsSlide5
Manx Cats
Selective fertilization for
sperm carrying Manx gene
T Gene versus Manx Gene?Slide6
Pembroke Welsh Corgis
T Gene missense mutationAlters T protein’s ability to bind to consensus DNA targetHomozygous lethalSlide7
Pembroke Welsh Corgis
Malformations if homozygotes survive to birthSlide8
Other Dogs
T Box mutation present in many, not all short tailed dogsMultiple genetic factors for tail phenotypesSlide9
Mice
T Gene and Brachyury discovered in tailless miceTwo genes influence taillessnessOne is dominant, the other recessive
Both present=taillessSlide10
Mice
Selective fertilization for heterozygote during segregation/recombinationHomozygote lethalEmbryonic developmentDifferences from Day 10Slide11
Hominoids
Bipedalism?Influence of coccyx versus tail on sacrumGrasping plus slow arboreal movements
Nacholapithecus
Slide12
Humans
Human tails are now an anomalyLittle evidence for genetic basisDisturbance in embryonic developmentSlide13
Humans
Tails present in embryoReach maximum length week 5Starts to regress by week 6Slide14
Overall Trends
T Gene/T-Box is really importantMultiple factors in tail phenotypesMalformations with taillessnessImpact on the spinal cord