CYTOGENETICS history of cyto and human genome

Karl Nägeli, 1842

First observed chromosomes in pollen cells.

Walther Flemming, 1870

Used aniline staining to visualize chromosomes during cell division.

Theodor Boveri & Walter Sutton, 1902

Linked chromosome behavior to Mendel’s laws of inheritance.

Thomas Hunt Morgan & Calvin Bridges, 1912

Discovered linkage and strengthened the Chromosome Theory of Inheritance.

Human chromosome number, 1921

Initially believed to be 48.

Joe Hin Tjio & Albert Levan, 1956

Corrected human chromosome number to 46.

Jérôme Lejeune, 1959

First diagnosed a human chromosomal aberration (trisomy 21 / Down syndrome).

Human genome

Entire genetic makeup of a human cell nucleus.

Genes in human genome

~35,000–50,000 genes (about 30,000 identified in HGP).

Non-coding DNA in genome

~95% of human DNA.

Human Genome Project goals

Identify all genes, determine DNA sequence, store data in databases, improve analysis tools, transfer tech to private sector, address ELSI.

Human Genome Project start & finish

Started 1990, finished April 2003 (two years early).

Human Genome Project working draft completed

June 2000.

Smallest genome in list

HIV – 9,700 bases, 9 genes.

E. coli genome size

4.6 million bases, 3,200 genes.

DNA identification in forensics

Identify suspects, exonerate innocent people.

DNA identification in conservation/agriculture

Identify endangered species, determine pedigree of breeds.

Ethical concerns of genetic info use

Privacy/confidentiality, discrimination or stigmatization.

Reproductive issues linked to genetic data

Informed consent, genetic info use in reproductive decisions.

Human genome size

3 billion bases, ~30,000 genes.

Mouse genome size

2.6 billion bases, ~30,000 genes.

Mustard weed genome size

100 million bases, ~25,000 genes.

Roundworm genome size

97 million bases, ~19,000 genes.

Fruit fly genome size

137 million bases, ~13,000 genes.

Yeast genome size

12.1 million bases, ~6,000 genes.