1 ©2016 Sami Khuri

June 2016 American University of Armenia Introduction to Bioinformatics

©2016 Sami Khuri

The Big Jaw Case Study

Introduction to Bioinformatics Sami Khuri

Department of Computer Science San José State University San José, California, USA

sami.khuri@sjsu.edu www.cs.sjsu.edu/faculty/khuri

Myosin gene mutation correlates with anatomical

changes in the human lineage by Hansell H. Stedman et al.

NATURE: VOL 428, 25 MARCH 2004

©2016 Sami Khuri

5 4 3 2 1 0 Millions of Years Ago

Ardipithecus ramidus

A. boisei

A. africanus

Australopithecus afarensis

A. robustus

Homo habilis

H. erectus

H. heidel- bergensis

H. neander- thalensis

Homo ergaster

H. sapiens A Possible Evolution Tree For Humans

Mutation lifted a constraint that inhibited brain growth

©2016 Sami Khuri

Powerful Masticatory Muscles •  Powerful masticatory muscles are found in

most primates, including chimpanzees and gorillas, and also in Australopithecus.

•  Masticatory muscles are considerably smaller in members of Homo.

•  The gene encoding myosin heavy chain (MYH) expressed in these muscles was inactivated by a frameshifting mutation after the lineages leading to humans and chimpanzees diverged.

©2016 Sami Khuri

A decrease in jaw-muscle size, produced by inactivation of MYH16, removed a barrier to the remodelling of the hominid cranium which consequently allowed an increase in the size of the brain.

©2016 Sami Khuri ©2016 Sami Khuri

2 ©2016 Sami Khuri

June 2016 American University of Armenia Introduction to Bioinformatics

©2016 Sami Khuri

MYH16: Myosin Heavy Gene Accession Number: BK001410 at NCBI (exon 19)

©2016 Sami Khuri

©2016 Sami Khuri ©2016 Sami Khuri