Table II.

Brief history of human genome analysis

1956	human chromosomes number = 46
1959 & 1960s	abnormalities in chromosome number, Down syndrome trisomy 21 [47, XY +21] Turner Syndrome 45, X chromosome mosaicism 46, XY/45, X
1970s	banding techniques, detect subtle aberrations of chromosome structure
1981	1st microdeletion Sx described in Kleberg Cytogenetics Laboratory; Prader-Willi Sx
1980s	fluorescence in situ hybridization or FISH; limit to small genomic interval
1990s	*telomere FISH – simultaneously assay chromosome ends
21st century The postgenomic era	Array CGH scan entire genome for submicroscopic CNV Personal genome sequence (WGS and WES)

^*demarcates a conceptual shift in thinking from single locus to multi locus testing