Final -- Cloning and Genomics

Dolly the sheep was derived from

Mammary gland cells

Success rate of cloning by nuclear transplantation

0.4% for Dolly, 3% for horses

2 kinds of embryos

Natural and nuclear transplant

Embryos are

Totipotent— highest potential, allowing for a complete organism and its supporting structures

Adult cells are

Pluripotent— slightly less versatile, limited to body cells only

Embryonic Stem Cells (ESC)

Primarily derived from IVF left over embryos (99%), or from aborted fetuses in the 70s

iPSC

Induced pluripotent stem cells; four transcription factors

Gene therapy

Target and alter specific genes— adult stem cells most commonly

CRISPR-Cas9

Now used to modify adult cells

Therapeutic Cloning

Nuclear Transfer for the purpose of creating cells to cure disease— obsolete

CRISPR-Cas9 is naturally found in

Archaea and prokaryotes

Sanger Sequencing

First gen DNA sequencing; 1000 bases at a time

Barbara McClintock

Studied transposable elements

Reverse transcriptase

Copy and paste

Transposase

Cut and paste

Composite transposons

Can move a whole gene

Size of human genome

21,000 genes and 3.1 billion bases

Prokaryotes and yeast have:

Dense genomes

Multicellular Eukaryotes have:

More genes, but huge genomes

What percentage of human genes are functional?

21%, but only 1.2% are protein coding

Functional sequences

RNA

Short tandem repeats (STR)

2 to 5 nucleotides repeated in a row

Pseudogenes

Defunct gene copies that resemble functional genes but are inactivated by mutations

Orthologs

Homologous genes (2 or more) that tend to have the same function and become different because of speciation

Paralogs

Duplicated homologous genes that tend to have different functions— they becomes different because of duplication

Unequal crossing over

Makes tandem duplicates, genes occur in a row

Transposable elements

Random location

Whole genome duplication

Lots of duplicates

Engrailed gene

Important in brain and nerve development in vertebrates

Hox genes

master control genes that dictate the head-to-tail body plan and organ placement in animals