The Big Jaw - SJSU Computer Science Departmentkhuri/AUA_2016/AUA_2016_CASE_STUDY_Jaw.pdf · The Big...

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 [email protected] 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

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Transcript of The Big Jaw - SJSU Computer Science Departmentkhuri/AUA_2016/AUA_2016_CASE_STUDY_Jaw.pdf · The Big...

June 2016 American University of Armenia Introduction to Bioinformatics

The Big Jaw Case Study

Introduction to Bioinformatics Sami Khuri

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

[email protected] 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

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

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.

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.