Identify the inheritance pattern from the pedigree chart shown:
A. X linked Dominant
B. X linked recessive
C. Autosomal Dominant
D. Y linked inheritance
Ans:D. Y-linked inheritance.
- Y-linked traits never occur in females, and occur in all male descendants of an affected male.
- The concepts of dominant and recessive do not apply to Y-linked traits, as only one allele (on the Y) is ever present in any one (male) individual.
- Only males are affected .
- It is passed from father to all sons.
- It does not skip generations.
Genes known to be Y-linked :
- ASMTY (acetylserotonin methyltransferase),
- TSPY (testis-specific protein),
- IL3RAY (interleukin-3 receptor),
- SRY (sex-determining region),
- TDF (testis determining factor),
- ZFY (zinc finger protein),
- PRKY (protein kinase, Y-linked),
- AMGL (amelogenin),
- CSF2RY (granulocyte-macrophage, colony-stimulating factor receptor, alpha subunit on the Y chromosome),
- ANT3Y (adenine nucleotide translocator-3 on the Y),
- SOX21 (known to cause baldness),
- AZF2 (azoospermia factor 2),
- BPY2 (basic protein on the Y chromosome),
- AZF1 (azoospermia factor 1),
- DAZ (Spermatogenes is deleted in azoospermia),
- RBM1 (RNA binding motif protein, Y chromosome, family 1, member A1),
- RBM2 (RNA binding motif protein 2), and
- UTY (ubiquitously transcribed TPR gene on Y chromosome).