| Term | Definition |
|---|
| PAR | small region on Y chromosome, highly homologous to the termini of the short and long arms of the X chromosome, it can undergo recomb in meiosis and contains large proporion of the Y chromosome genes |
| MSY | 95% of the chromosome much heterochromatin and few genes |
| SRY | sex determining region of the Y chromosome (TDF) |
| DAZ | family of genes that when deleted, are associated with azoospermia |
| USP9Y | unknown function, but required for normal spermatogenesis |
| Cause of Variable Expressivity | due to other loci in their genetic background (modifier genes) |
| Locus Heterogeneity | located on different human chromosomes, and also expressed in different cell types and/or tissues |
| Modifying Loci | genes that modify the expression of another gene |
| Environmental Factors | Himalayan rabbits and Siamese cats, coat color at extremities |
| Sex-limited traits | expression of an autosomal trait is limited to one sex, i.e. milk production, prostate cancer, male-limited precocious puberty |
| Sex influenced traits | mode of expression of the autosomal trait is modified by the sex of individual carrying the allele, male pattern baldness is dominant in males, but recessive in females |
| Marfan Syndrome and Neurofibromatosis I | show variable expression |
| Huntington Disease | delayed onset, mutation on HSA4p16.3, modifying genes affect the age of onset of the symptoms |
| PKU | pleiotropy disease and gene x environment interaction |
| Somatic Mosaicism | event bringing about the mosaic condition occurred post-zygotically. The abnormal cell line's phenotype cannot be passed on to progeny |
| Germline mosaicism | the abnormal cell line is only present in the gonads; responsible for recurrence of a dominant phenotype when neither parent is affected. |
Combine with other sets
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