Explanation on genotypes notations

Question

[MAPK]

Hi Everyone,

I am new in the field of genetics. I was reading a paper and came up with these (*) indications of genotypes particularly in these sentences:

1. The most frequently detected alleles of Holstein x Zebu were DRB3*16, *51, *23, *11, *8, and *1, accounting for 61.12%.
2. It is important to note that no individuals with known homozygous GoF alleles (CYP2C19*17/*17) were included in this analysis.

Now, my questions:

1. Does the asterisk sign indicate nucleotide changes in those particular position (*16, *51, *23, *11, *8, and *1) of the gene mentioned above in sentence 1? What does it mean when it says the detected alleles are *16, *51, *23, *11, *8, and *1?
2. What does *17/17 (CYP2C19*17/*17) indicate here?

Thank you for helping me understand this.

Answer 1

[rbagnall]

Genes encoding the major histocompatibility complex molecules (e.g. DRB1 encoding major histocompatibility complex, class II, DR beta 1) are highly polymorphic. HLA 'alleles' are combinations of many different polymorphic variants. There is a need for a systematic way to name all the different HLA alleles, i.e. The Nomenclature for Factors of the HLA System.

The notation is described here.

Nomenclature         Indicates
HLA                  the HLA region and prefix for an HLA gene
HLA-DRB1             a particular HLA locus i.e. DRB1
HLA-DRB1*13          a group of alleles which encode the DR13 antigen or sequence homology to other DRB1*13 alleles
HLA-DRB1*13:01       a specific HLA allele

You can view alignments of different HLA alleles here, and click on 'alignment'