Class Notes (839,590)
Canada (511,419)
HMB265H1 (242)

Notes taken during lecture. My laptop battery ran out around ten minutes before lecture ended, so the notes are incomplete. Apologies.

4 Pages

Human Biology
Course Code
Stephen Wright

This preview shows page 1. Sign up to view the full 4 pages of the document.
LECTURE March 24, 2011 4 major classes of chromosomal rearrangements deletions, duplications, inversions, translocations Most are caused by double-stranded DNA breakers causing these chromosomal rearrangements Deletions = specific segment of chromosome is broken in two separate locations, this piece leaves Duplication = segment of DNA duplicated and inserted in another area Inversion = piece of chromosome that is broken, excised, inverted 180 degrees, and reinserted Translocation = piece of chromosome has shifted to another position How can these changes in chromosome structure studied? o Salivary gland chromosomes Very large because they undergo endoreplication Replication of DNA without nuclear division, without cell division Homologous chromosomes stacked on top of each other Many of these chromosomes are actually bound to each other at chromosomal centre Very easily visualized under microscope Charactiersic banding pattern o To show areas of transcipritonal activity and non-activity Stain and look under microscope Locations of bands are same from animal to animal unless there are chromosomal rearrangements Banding patterns have been mapped Deletions X-rays are major cause If piece of chromosome is not religated in the position, deletion Intragenic deletion only one gene is affected Multigenic when many genes are deleted o Produce more severe phenotype than intragenic Df = deficiency Usually inviable Homozygotes usually inviable Unmasking of recessive Heterozygotes depend Gene inbalance Haploinsufficiency occurring Deletion visualized Deletion loop forming When pairing during meiosis, CDE has no pairing partner, so loop created Deletions are important o Phenomenon of pseudodominance allows this o Normal contains recessive allele of scarlet gene o Deleted region encompasses scarlet gene o Phenotype = scarlet eyes
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.