Ch 21 - Ch 21: 586 - 590 – Sex Determination in...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Ch 21: 586 - 590 – Sex Determination in Drosophila I. Previously: sex determined by X chromosome: autosome ratio II. Regulation Cascade Model A. X:A=1=Female: Sxl gene transcribed w/ regulated splicing SXL protein regulates splicing of tra pre-mRNA TRA protein regulates splicing of dsk pre-mRNA DSX-F represses male-specific gene expression Female B. X:A=0.5=Male: default splicing of pre-mRNA includes early stop codon for sxl, tra, & dsx DSX-M represses female-specific expression Male C. initial switch for sex determination 1. X chrom have sisterless numerator genes sis-a, sis-b, & sis-c & Autosome has a deadpan (dpn) denominator gene these protein products interact a. numerator subunits can form homo/hetero-dimers w/ denominator subunits b. females – 2 numerator:1 denominator numerator homodimers (TF that can activate Sxl expression) c. males – 1 numerator:1 denominator no/insufficient numerator homodimers 2. Process a. P E (early embryogenesis, due to homodimers) = made of...
View Full Document

This note was uploaded on 02/09/2010 for the course BIOL 3301 taught by Professor Hannig/miller during the Spring '10 term at Dallas.

Ask a homework question - tutors are online