Ch_4_Wood_Sex-2

Ch_4_Wood_Sex-2 - Sex EukaryoticGenome Compartments Nuclear...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Sex
Background image of page 1

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

View Full DocumentRight Arrow Icon
Eukaryotic Genome  Compartments  Nuclear DNA Autosomes Sex Chromosomes (X and Y, or Z and W) Mitochondrial DNA (mtDNA) Chloroplast DNA (cpDNA) in plants and algae X Y Cyt b ND6 ND5 ND4 ND1 ND2 COX I COX II A8 A6 ND3 ND4L D-LOOP: HVS-I and II OH OL COX III 12S rRNA 16S rRNA MtDNA
Background image of page 2
Haploid vs. diploid Diploid = 2n, haploid = n, where n = # of chromosomes Meiosis reduces the amount of genetic material by half (2n→n) Fertilization restores the diploid complement
Background image of page 3

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

View Full DocumentRight Arrow Icon
Gamete formation (girls born with  oocytes  suspended in  Prophase I) Mitosis produces germ cells (spermatogonia and oogonia) A male germ cell meiotically divides into 4 sperm A female germ cell meiotically divides into 1 egg (ovum) and 2 polar bodies
Background image of page 4
Male and female are defined according to the size of the gametes that they produce Males produce small gametes Females produce large gamete Hermaphrodites have both female and male reproductive structures common in invertebrates and some fish in humans, the term hermaphrodite has also been used to describe ambiguous genitalia and gonadal mosaicism term intersex (not hermaphrodites) is preferred term by medical professionals Linneaus, who created binomial nomenclature, 1st used the symbols to denote sex of plants
Background image of page 5

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

View Full DocumentRight Arrow Icon
XX-XY, where XX = and XY = Humans and most mammals Contain a pseudoautosomal region where the X and Y can recombine XX-XO, where XX = and a single X (XO) = Grasshoppers, moths ZZ-ZW, where ZW = and a ZZ = Birds, snakes, butterflies, some amphibians, and some fishes Heterogametic has two different sex chromosomes homogametic sex has the same Hemizygous – individuals who are neither homozygous or heterozygous (e.g. human males, snake females) Sex Determination - 1
Background image of page 6
Sex Determination - 2 Haplodiploidy Sex determination is based on the number of chromosomes sets e.g. ♂ - n, ♀ - 2n Male develop from an unfertilized egg Common in Hymenoptera (bees, wasps, and ants)
Background image of page 7

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

View Full DocumentRight Arrow Icon
Sex Determination - 3 Genic Sex-Determining System Autosomal gene causes sex Plants and protozoans Drosophila have 4n chromosomes - 3 pairs of autosomes, 1 sex chromosome pair ♀ XX and ♂ XY the Y does not determine sex sex is determined by the X to autosome ratio X:A ratio of 1 produces a ♀ X:A ratio of 0.5 produces a ♂ X:A ratio of 1 - 0.5 produces an intersex X:A ratio of >1.0 ♀ (metafemale) with problems
Background image of page 8
Sex Determination - 4 Environmental Sex Determination Found in many reptiles where water temperature during development influences sex Marine mollusk (slipper limpet) where position in stack influences sex
Background image of page 9

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

View Full DocumentRight Arrow Icon
Sex Chromosomes in Humans X chromosome Contains more than 1,500 genes Acts as a homolog to Y chromosome in males (i.e. pairs with the X) Alleles found only on the X are X-linked
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/30/2010 for the course ECOL 320 taught by Professor Weinert during the Spring '07 term at Arizona.

Page1 / 54

Ch_4_Wood_Sex-2 - Sex EukaryoticGenome Compartments Nuclear...

This preview shows document pages 1 - 11. Sign up to view the full document.

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