TEMA 5. ANÁLISIS DE GENEALOGÍAS

TEMA 5. ANÁLISIS DE GENEALOGÍAS
SÍMBOLOS UTILIZADOS
OMIA 000202-9685 : Coat colour, albinism in Felis catus
In other species: cattle , chicken , dog , horse , rabbit , sheep , Sumatran tiger , western chorus
frog , grass carp , golden hamster , gray short-tailed opossum , raccoon , meadow voles , water
buffalo , Arizona pocket mouse , nutria , eastern chipmunk , rufous rat-kangaroo , hippopotamus ,
hares , northern pocket gopher , North American deer mouse , Norway rat , ass , Japanese medaka
, rainbow trout , brown bear , , American mink , African green monkey
Possible human homologue (MIM number): 203100
Single locus: yes
Mode of inheritance: Autosomal Recessive
Considered a defect: yes
Mutation known: yes
Cross-species summary Causative : Congenital lack of pigment in all parts of the body. Due to a
non-functional form of the enzyme tyrosinase.
Molecular basis: In a landmark study, Lyons et al. (2005) confirmed what had long been suspected,
namely that the trademark Burmese and Siamese coat colours are due to mutations in the tyrosinase
(TYR) gene. The Burmese phenotype is due to a 715G>T transversion in exon 1, resulting in a
G227W amino-acid substitution; and the Siamese phenotype is due to a 940G>A transition in exon
2, resulting in a G302R amino-acid substitution.
Associated gene:
Symbol
Description
Species
TYR
tyrosinase (oculocutaneous albinism IA)
Felis catus
1
CARÁCTER AUTOSÓMICO RECESIVO: Albinismo
-Normalmente se saltan generaciones
-Se manifiestan en ambos sexos
-Los descendientes afectados suelen tener progenitores no afectados
-Aparece mas frecuentemente en descendientes de cruzamientos consanguíneos
OMIA 000187-9615 : Chondrodysplasia in Canis lupus familiaris
In other species:domestic pig , cattle , sheep , domestic cat
Mammalian Phenotype Ontology (MPO) number: MP:0002657
Single locus: yes
Mode of inheritance: Autosomal
Considered a defect: yes
Causative mutation known: yes
Cross-species summary: Abnormal growth of cartilage, leading to disproportionate dwarfism.
Associated gene:
Symbol
Description
Species
FGF4
fibroblast growth factor 4
Canis lupus familiaris
References
2 Smit, JJ., Temwitchitr, J., Brocks, BA., Nikkels, PG., Hazewinkel, HA., Leegwater, PA. : Evaluation of
0 candidate genes as a cause of chondrodysplasia in Labrador retrievers. Vet J 187:269-71, 2011.
1 Pubmed reference: 20018534.
1
2
CARÁCTER AUTOSÓMICO DOMINANTE: Acondroplasia
-Raramente se saltan generaciones
-Se manifiestan en ambos sexos
-Todos los individuos afectados tienen un progenitor afectado
-Los progenitores no afectados, no transmiten el rasgo
OMIA 000437-9615 : Haemophilia A in Canis lupus familiaris
In other species: domestic cat , horse , domestic pig , sheep , , cattle
Possible human homologue (MIM number): 306700
Single locus: yes
Mode of inheritance: X-linked recessive
Considered a defect: yes
Causative mutation known: yes
Cross-species summary: Also called factor VIII deficiency. Impaired coagulability of the
blood, with a consequential strong tendency to bleed, due to a deficiency of the clotting factor
VIII. Since the gene for this factor is located on the X chromosome, the disorder is expected
to be X-linked. In domesticated animals, the disorder has been reported in a large range of
species, but in no case has the molecular basis yet been determined.
Associated gene:
Symbol
F8
Description
coagulation factor VIII, procoagulant component
Species
Chr acc
Chr name
Canis lupus familiaris
NC_006621.
2
X
3
Hemofilia: recesivo ligado al X
-Afecta con mayor frecuencia a los machos
-El rasgo se suele saltar generaciones
-Nunca se transmite del progenitor al descendiente macho
-Todas las hembras descendientes de machos afectados son portadoras
CARACTERES DOMINANTES LIGADOS
AL CROMOSOMA X
• Estan
afectados ambos sexos, pero es mas
frecuente en hembras
• Los machos afectados transmiten la “condición “ a
todas sus descendientes hembras, pero a ningún
macho
• Las hembras afectadas transmiten la condición a
la mitad de sus descendientes tanto machos como
hembras
•No suele saltar generaciones
Ej.:
Ej.: Raquitismo hipofosfatemico
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HERENCIA LIGADA AL CROMOSOMA Y
¾Los genes de la región diferencial del cromosoma Y son
heredados
solamente
por
los
descendientes
machos
(provenientes del progenitor macho).
¾No salta generaciones
¾A excepción de los genes relacionados con la determinación
del sexo, no se ha demostrado con claridad el ligamiento al Y
de ningún fenotipo humano.
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