1 / 28

Chromosomes and Inheritance

Chromosomes and Inheritance. Autosomes vs. sex chromosomes. Autosomes = the pairs of chromosomes that are the same in males and females. In humans, these are chromosomes # 1 - # 22. sex chromosomes = differ between males and females of a species: differ physically and in the genes

Download Presentation

Chromosomes and Inheritance

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chromosomes and Inheritance

  2. Autosomes vs. sex chromosomes Autosomes = the pairs of chromosomes that are the same in males and females In humans, these are chromosomes # 1 - # 22

  3. sex chromosomes = differ between males and females of a species: differ physically and in the genes they carry In humans, chromosome # 23

  4. female x x xx & male xy y x & sex determination in humans: female gives: male gives:

  5. Alleles alleles are different forms of a given gene ex. gene = tongue rolling tongue roller vs. non-roller

  6. the alleles from mom and dad may be the same, may be different chromosome # 14 tongue rolling gene from mom tongue rolling gene from dad

  7. Each person carries 2 copies of each gene (on their autosomes) Genotype = the gene forms, or alleles someone carries

  8. Genotypes RR- if they carry the same allele on both chromosomes -> HOMOZYGOUS Rr- if they carry different alleles -> HETEROZYGOUS

  9. Phenotype = the physical or physiological expression of those alleles

  10. alleles can have different relationships to each other dominant --- recessive 1. a dominant allele, when found in the heterozygous condition, overrides the recessive allele Rr -> will result in a tongue roller

  11. roller roller non-roller GENOTYPE PHENOTYPE RR = homozygous dominant Rr = heterozygous rr = homozygous recessive

  12. 2. incomplete dominance

  13. 3. multiple alleles with codominance ex. blood type

  14. ex. a person born with 6 fingers Genetic Disorders 1. genetic abnormality- an uncommon version of a trait

  15. 2. genetic disorder- an inherited condition that will result in mild to severe health problems. ex. cystic fibrosis

  16. 3. syndrome- a set of symptoms that characterize a given disorder

  17. Autosomal dominant inheritance = trait will typically appear in every generation HH or Hh Ex. Huntington’s disorder (nervous system)- typically fatal in 40’s or 50’s Why does gene stay in population? its effects occur post-reproduction

  18. Autosomal recessive inheritance- trait (disorder) shows up less often in the population because the trait can be masked by the dominant allele Ex. galactosemia: gg lactose galactose glucose-1-phosphate glucose X results in a buildup of galactose in blood… damage to eyes, liver, brain

  19. male female x-linked recessive traits- gene is only found on the x chromosome- not the Y! xAxA xAxa xaxa xAy xay 33.3% 50%

  20. Hemophilia in Royal Families in Europe I-1 = King George III III-1 and III-2 = Prince Albert and Queen Victoria IV-5 and IV-6 = Alice of Hesse and Ludwig IV of Hesse V-13 and V-14 = Alix and Nicholas II (Tsar of Russia) VI-16 = Alexei VIII-1 = Prince Charles

  21. Changes in Chromosome Number aneuploidy= the condition of having less than or more than the normal diploid number of chromosomes polyploidy- condition of having 3 or more entire sets of chromosomes (lethal in humans)

  22. Down syndrome (trisomy 21): The result of an extra copy of chromosome 21. Down syndrome affects 1:700 children and alters the child's phenotype either moderately or severely.

  23. cause of aneuploidy = NONDISJUNCTION Failure of paired chromosomes to disjoin (separate) during cell division so that both chromosomes go to one daughter cell and none to the other.

  24. Patau syndrome (trisomy 13): serious eye, brain, circulatory defects as well as cleft palate. 1:5000 live births. Children rarely live more than a few months.

More Related