THE MONOHYBRID CROSS FOLLOWING THE INHERITANCE OF ONE TRAIT.
Variation and the Monohybrid Cross
-
Upload
trinhtuyen -
Category
Documents
-
view
232 -
download
0
Transcript of Variation and the Monohybrid Cross
![Page 1: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/1.jpg)
Variation and the Monohybrid Cross
Higher Biology
![Page 2: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/2.jpg)
Significance of meiosisAllele: different forms of the
same gene
‘Meiosis provides the opportunity for new combinations of the existing alleles of genes to arise”
![Page 3: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/3.jpg)
Independent assortment of chromosomes
• Homologous pairs line up at equator during first meiotic division
• Final position of any one pair is random relative to any other
• Second meiotic division brings about independent assortment of chromosomes
• This may lead to new phenotypes in the next generation
![Page 4: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/4.jpg)
![Page 5: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/5.jpg)
Crossing over and separation of linked genes• Chromosome is aligned with its
homologous partner during first meiotic division
• Portions of chromatid exchanged at points called chiasmata
![Page 6: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/6.jpg)
Chiasmata• Chromatids become broken• Broken end of one joins with that of
another• Alleles of linked genes can become
separated• Formation of new allele combinations• Formation of new phenotypes
![Page 8: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/8.jpg)
Importance of Variation• Helps species adapt to a changing
environment
• ‘Survival of the fittest’ then occurs as a result of natural selection
![Page 9: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/9.jpg)
Monohybrid Cross• Cross between true-breeding parents
with different alleles of the same gene
• Genotype: the alleles the individual possesses of a particular gene
• Phenotype: physical appearance of an individual
![Page 10: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/10.jpg)
Mendel’s First Law• The principle of segregation
• alleles of a gene exist in pairs
• when gametes form– members of each pair pass into different
gametes– each gamete contains only one allele of
each gene
![Page 11: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/11.jpg)
![Page 12: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/12.jpg)
Incomplete dominance
![Page 13: Variation and the Monohybrid Cross](https://reader035.fdocuments.us/reader035/viewer/2022062223/5881ee4c1a28ab3f198b79d3/html5/thumbnails/13.jpg)
This powerpoint was kindly donated to www.worldofteaching.com
http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.