Presentation on theme: "Human Heredity Chapter 14. Human Chromosomes Chromosomes are only visible during cell division (mitosis/meiosis). To analyze chromosomes, biologist photograph."— Presentation transcript:
Human Chromosomes Chromosomes are only visible during cell division (mitosis/meiosis). To analyze chromosomes, biologist photograph cells during mitosis and align the chromosomes in homologous pairs. This picture is known as a karyotype
Types of Chromosomes On a human karyotype: Chromosome pairs 1-22 are known as autosomes. – They code for traits that are not related to sex. – Both males and females have the same type Chromosome pair 23 contains the sex chromosomes. – Males have XY and females have XX.
SEX CHROMOSOMES CAN CARRY OTHER GENES TOO = ___________________ SEX LINKED TRAITS These traits show up in different _______________ in males and females because they move with the sex chromosomes percentages
Y-LINKED GENES: Genes ______________ chromosome EXAMPLE: Hairy pinna _________genes _____ show up in males Y linked carried on Y ONLY
____________ GENES: are carried on the X chromosome X-linked recessive disorders show up _____________ in ______ than females because males only have ______ X chromosome. MALES X-LINKED ONE MORE frequently
HEMOPHILIA CAUSE: Mutation in genes for __________________ carried ______ chromosome Blood clotting proteins are missing so person with this disorder can’t stop bleeding when injured; can ________________ from minor cuts or suffer internal bleeding from bruises or bumps. bleed to death Blood clotting proteins on X
Muscular Dystrophy CAUSE: deletion in gene that codes for a _______________ On X Chromosome Results in ____________________ and loss of ___________________ http://www.cadenhead.org/workbench/gems/jerry-lewis-telethon.jpg http://www.tokyo-med.ac.jp/genet/chm/dei.gif muscle protein weakening skeletal muscle 1 out of 3000 males in US
COLORBLINDNESS CAUSE: Mutation in one of three genes for _______________ carried on X chromosome Persons with this disorder have trouble distinguishing colors. Seen in 1 in 10 males 1 in 100 females Color vision http://gizmodo.com/gadgets/peripherals/samsung-develops-lcd-for-colorblind-036306.php
When Harry Met Sally… Harry and Sally are two normal vision adults who have a color blind son. – B – normal vision b – color blind – What are the genotypes of Harry and Sally? X B Y, X B X b Show the cross between Harry and Sally. http://www1.istockphoto.com/file_thumbview_approve/23 41727/2/istockphoto_2341727_cute_cartoon_couple_drinki ng_vector.jpg
When Harry Met Sally… Give all of the possible genotypes and phenotypes of their offspring. _________ – normal vision daughter ________ – normal vision daughter (carrier) ________ – normal vision son ________– color blind son Sally’s dad has normal vision. Is Sally’s Mom colorblind? She could be colorblind, or she could be a carrier for the colorblindness trait. http://www1.istockphoto.com/file_thumbview_approve/23 41727/2/istockphoto_2341727_cute_cartoon_couple_drinki ng_vector.jpg
PEDIGREE CHARTS Show the relationships within a family to study one particular observable trait/phenotype. Refer to page 342 in text. Circle=female Square=male Horizontal line=marriage Vertical line and bracket=children Shaded=person expresses trait Unshaded=person does not express trait.