chromosomes, mapping, and the meiosis-inheritance connection
DESCRIPTION
Chromosomes, Mapping, and the Meiosis-Inheritance Connection. Chapter 13. HUMAN GENETICS. Introduction 46 chromosomes in each cell (23 pairs) Autosomes: all chromosomes except sex chromosomes (22 pairs) Sex chromosomes: determine gender (1 pair). Sex determination XX = female - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/1.jpg)
Chromosomes, Mapping, and the Meiosis-Inheritance Connection
Chapter 13
![Page 2: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/2.jpg)
HUMAN GENETICS
![Page 3: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/3.jpg)
I. IntroductionA.46 chromosomes in each
cell (23 pairs)B.Autosomes: all
chromosomes except sex chromosomes (22 pairs)
C.Sex chromosomes: determine gender (1 pair)
![Page 4: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/4.jpg)
![Page 5: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/5.jpg)
1.Sex determinationa)XX = femaleb)XY = male
2.During meiosis, each egg from the female gets an X; 1/2 male sperm get X, 1/2 get Y
3.Males determine gender of offspring!a)Except in birds and reptiles
where female is XY and male is XX
![Page 6: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/6.jpg)
![Page 7: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/7.jpg)
II. Studying human geneticsA.Difficult because
1. Long generations (25 yrs)2. Single births3. Ethical concerns
![Page 8: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/8.jpg)
B.Methods for studying humans1.Pedigrees: record that shows
how a trait is inherited within a family
![Page 9: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/9.jpg)
9
![Page 10: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/10.jpg)
2. Population sampling1. Selecting a small # of people to
represent an entire population2. Must be a random sample3. Ex: through random sampling,
researchers discovered that 65% of people in US taste PTC, 35% cannot
![Page 11: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/11.jpg)
3. Identical twin studiesa) Identical genetic codesb)Separated at birth: study which
traits are genetic(Nature) & which are environmental (Nurture)
![Page 12: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/12.jpg)
![Page 13: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/13.jpg)
13
Human Genetic Disorders
Some human genetic disorders are caused by altered proteins.
the altered protein is encoded by a mutated DNA sequence
the altered protein does not function correctly, causing a change to the phenotype
![Page 14: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/14.jpg)
14
![Page 15: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/15.jpg)
III. Inheritance of human traitsA. Dominant traits
1. Polydactyly - extra fingers & toes
2. Dwarfism - small size3. Curly hair4. Huntington disease - nervous
disorder5. Piebaldness - white patches of
hair
![Page 16: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/16.jpg)
![Page 17: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/17.jpg)
Vitiligo=AutoImmune
Piebaldness=Genetic
![Page 18: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/18.jpg)
B.Recessive traits1.Straight hair2.Freckles3.Albino4.Cystic fibrosis - lung disorder5.Deafness6.PKU - nervous disorder
![Page 19: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/19.jpg)
19
Odds of having a child with the disease?
![Page 20: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/20.jpg)
C.Codominance1.Sickle cell anemia - irregularly
shaped red blood cells• O allele = healthy(HH)• 1 allele = mild case(HS),
resistant to malaria• 2 alleles = severe case(SS)
![Page 21: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/21.jpg)
21
Sex Chromosomes
In each female cell, 1 X chromosome is inactivated and is highly condensed into a Barr body.
Females heterozygous for genes on the X chromosome are genetic mosaics.
![Page 22: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/22.jpg)
22
![Page 23: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/23.jpg)
F. Sex-linked traits1. Genes located on X chromosome2. Males only have one X, so only
have one allele controlling these genes
3. Males more likely to have disorders that are sex-linked because they only need 1 recessive allele
![Page 24: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/24.jpg)
![Page 25: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/25.jpg)
4. Carrier: someone who has one allele for a disorder -- does not have the disease but can pass it on to children
5. Only women can be carriers for sex-linked traits
6. Examples: hemophilia, muscular dystrophy, colorblindness
![Page 26: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/26.jpg)
Hemophilia in the Royal Families of Europe
![Page 27: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/27.jpg)
27
![Page 28: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/28.jpg)
7. Color visiona)XC=Color Vision, Xc=colorblindb)Males - 8% colorblind (XcY)c) Females - 1% colorblind (XcXc)
Normal
Red-Green
Total
![Page 29: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/29.jpg)
![Page 30: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/30.jpg)
What are the chances for a healthy dad and a mom who is a carrier for colorblindness to have a child that
is colorblind?
![Page 31: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/31.jpg)
IV. Genetic disordersA. Nondisjunction: failure of
chromosomes to separate during meiosis
1. Normal = 23 chromosomes2. Abnormal = 22 or 24
![Page 32: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/32.jpg)
32
![Page 33: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/33.jpg)
3. Monosomy: too few chromosomes, one chromosome left unpaireda)Turner syndrome: female with
only 1 X chromosomeb)Short stature, sterile
![Page 34: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/34.jpg)
4. Trisomy: too many chromosomes, extra copy of onea)Down’s syndrome: trisomy 21b)1 in 1400 when mother under age
25, 1 in 100 by age 40
![Page 35: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/35.jpg)
35
Human Genetic Disorders
Nondisjunction of sex chromosomes can result in:
XXX triple-X femalesXXY males (Klinefelter syndrome)XO females (Turner syndrome)OY nonviable zygotesXYY males (Jacob syndrome)
![Page 36: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/36.jpg)
B.Detecting genetic disorders1. Physical characteristics - features,
disabilities2. Ultrasound - pictures of baby in
utero using sound waves3. Amniocentesis - sample of fluid from
around baby, can examine baby’s cells
http://www.biology.iupui.edu/biocourses/n100/2k4csomaldisordersnotes.html
![Page 37: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/37.jpg)
http://www.katie.com/babyblog/archives/000538.html
![Page 38: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/38.jpg)
http://www.katie.com/babyblog/archives/000538.html
![Page 39: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/39.jpg)
39
![Page 40: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/40.jpg)
40
![Page 41: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/41.jpg)
4.Karyotype: picture of a person’s cromosomes • taken from any cells -- blood
in adults, amnio for baby
Normal Trisomy 21
![Page 42: Chromosomes, Mapping, and the Meiosis-Inheritance Connection](https://reader036.vdocuments.site/reader036/viewer/2022062813/568164ce550346895dd6f5ed/html5/thumbnails/42.jpg)
42