Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance...
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Transcript of Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance...
![Page 1: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/1.jpg)
Meiosis and Sex-linked traitsCh. 10.4-10.5
![Page 2: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/2.jpg)
Objectives
1. Explain chromosome theory of inheritance
2. Understand genetic linkage
3. Explain sex-linked genes and why more common in males
![Page 3: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/3.jpg)
Chromosome Theory of Inheritance
• Mendel’s findings were not widely accepted at first• During the 1900’s, parallels discovered between
genes and chromosomes• This is referred to as the chromosome theory of
inheritance:• Chromosome Theory of Inheritance:
– Genes located on chromosomes
– accounts for inheritance patterns
![Page 4: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/4.jpg)
Chromosome Theory of Inheritance
• Remember, diploid individuals have 2 sets of homologous chromosomes – One from mom, one
from dad
• Gene locus:– Alleles of a gene reside
at same location
![Page 5: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/5.jpg)
Genetic Linkage and Crossing Over
• Genetic Linkage:– Tendency for alleles on
one chromosome to be inherited together
• Closer the genes, the greater the genetic linkage
• Farther apart, greater chance of separation
![Page 6: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/6.jpg)
![Page 7: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/7.jpg)
Sex Linked Genes
• What two sex chromosomes make up a male? Female?– Male = XY, Female = XX
• Which chromosome is physically larger?– The X. It can hold a lot more genetic info
• Sex linked gene:– Any gene on a sex chromosome
![Page 8: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/8.jpg)
Sex-linked Disorders• Many sex-linked disorders
are recessive alleles – Let’s say that white eyes in
fruit fly is an example
• Disorders always carried on X chromosome (Y doesn’t have any room, too small)
• What does all this mean?
![Page 9: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/9.jpg)
Sex-linked Disorders• If disease is recessive and always carried on X chromosome, then
females (XX), will most likely have dominant form of allele on other chromosome --> don’t get disorder.
• If males (XY) have allele for disorder on their X chromosome, they will get disorder because Y chromosome doesn’t carry alleles.
![Page 10: Meiosis and Sex-linked traits Ch. 10.4-10.5. Objectives 1.Explain chromosome theory of inheritance 2.Understand genetic linkage 3.Explain sex-linked genes.](https://reader036.fdocuments.in/reader036/viewer/2022072015/56649ece5503460f94bdab75/html5/thumbnails/10.jpg)
Rare!