Lecture 5 - Sequencingofthehumangenomehasshownthatthere

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Sequencing of the human genome has shown that there are 25,000-30,000 genes encoded by our DNA. Yet there are only 23 chromosomes. Therefore each chromosome must contain many different genes. We know this must be true since there many different sex- linked traits have been discovered for genes that must be on the X chromosome.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Fig. 5.28
Background image of page 2
Mendel established that genes are different chromosomes independently assort--that is, are distributed to gametes independently of each other. How do genes on the same chromosome segregate during meiosis?
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
A A a b b a B B A b A b a B a B 2 Ab:2aB A a b b a A B B A B A B b a b a 2 AB:2ab Remember that independent assortment predicts an equal number of parental and recombinant gametes
Background image of page 4
What happens during meiosis to genes that we know are on the same chromosome?  Do they always segregate together?  Do they independently assort? Two X-linked traits in fruit flies:  eye color:   White Red Body size:   Normal Minature
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Female X Male F1 Male X ? F2 test cross: phenotypes of the F2 progeny determined solely by the chromosome inherited from the mother Female
Background image of page 6
Genotypes and phenotypes expected if w and min are completely linked (that is the chromosomes cannot change during meiosis):
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Genotypes and phenotypes expected if w and min independently assort:
Background image of page 8
Observed types and numbers of progeny in the F2: Red-eyed, normal body   791 white-eyed, minature body   750 red-eyed, minature body   455 white-eyed, normal body   445 Recombinant flies are detected--therefore genes on the same chromosome can be separated--but are they assorting independently?
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
If w and m are segregating independently from each other during meiosis, then the  number of parental and recombinant types should be equal.  Is that the case here? Red-eyed, normal body   791 white-eyed, minature body   750 red-eyed, minature body   455 white-eyed, normal body   445 Scientists don’t guess-they do  statistical analyses to see how  confident they can be of a particular conclusion.
Background image of page 10
χ 2 : 1. Determine what the expected values for each class should be based on the null hypothesis. χ
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/27/2010 for the course BIO 89329 taught by Professor Hollingsworth during the Spring '10 term at SUNY Stony Brook.

Page1 / 37

Lecture 5 - Sequencingofthehumangenomehasshownthatthere

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online