AP_Bio_-_Ch_15_Notes

AP_Bio_-_Ch_15_Notes - Ch 15. Chromosome Theory of...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Ch 15. Chromosome Theory of Inheritance (1902) 1) Genes are located @ specific loci on chromosomes Time Line 1860’s Mendel & his peas. Laws of Segregation & Independent Assortment 1875 Process of Mitosis Worked out 1890 Process of Meiosis Worked out 1900 Botanists rediscover Mendel’s work/theories. 1902 Sutton, Boveri, and others noticed parallels between Mendel’s factors and chromosomal behavior. Thomas H Morgan: Columbia University Drosophila melanogaster (Fruit flies) D. melanogaster Easy to culture 4 pairs of chromosomes r-selected (opportunistic) populations (ch.52) fast breeding, short life span, large #’s of offspring. Humans are K-selected (equilibrial) populations. 1
Background image of page 1

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

View Full DocumentRight Arrow Icon
Vocab for Morgan’s experiments: Wild type. The most frequently seen phenotype Mutant. Any phenotype other than the wild type Genetic symbols established by Morgan: 1) Based on the 1 st mutant of each gene 2) Lower case = recessive w 3) Capitalized = dominant 4) Super script + = wild type w + Sex Linked Traits: White eyes in Drosophila Female X Male w + w F1 all wild type w + shows dominance F2 w + : w = 3:1 which was also expected, but the only white eyed offspring were male. Deduced that the w is on the X chromosome. So any male with the w had no w + to dominate it. Any sex linked gene/allele is only found on one chromosome from only gamete, thus the terms heterozygote, or homozygote are not applicable. Hemizygote is the term for a sex linked gene. 2
Background image of page 2
Sex linked genes will only be expressed in the male F2 offspring if your P cross is a homozygous female with a sex- linked male. (See fig 15.9 for expected phenotypic ratios.) Can a female show a sex linked recessive trait? Try a test cross:
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 9

AP_Bio_-_Ch_15_Notes - Ch 15. Chromosome Theory of...

This preview shows document pages 1 - 4. Sign up to view the full document.

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