12.2 complex patterns of inheritance. complex patterns of inheritance mendel’s experiments show...
TRANSCRIPT
![Page 1: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/1.jpg)
12.2 Complex patterns of inheritance
![Page 2: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/2.jpg)
Complex patterns of inheritance
Mendel’s experiments show simple inheritance with recessive and dominant alleles
Some patterns of inheritance are more complex
![Page 3: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/3.jpg)
Complex patterns of inheritance
Incomplete dominance Codominance Multiple alleles Sex-linked inheritance Polygenic inheritance Environmental factors
![Page 4: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/4.jpg)
Incomplete dominance
Phenotype of the heterozygote is in between the phenotypes of the homozygotes
RR=red pigment
R1R1=white, no pigment
RR1=pink
![Page 5: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/5.jpg)
Codominance
Phenotypes of both homozygotes are produced in heterozygote, both alleles are expressed equally
BB=black feather
WW= white feather
BW= checkered
![Page 6: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/6.jpg)
Multiple alleles
Traits controlled by more than two alleles Each pigeon has two alleles
for feather color, but thereare many possible alleles
![Page 7: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/7.jpg)
Sex-linked inheritance
In humans have 46 chromosomes, 23 pairs 22 pairs autosomes one pair sex chromosomes, determine sex
![Page 8: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/8.jpg)
Sex-linked inheritance
Sex-linked traits are controlled by genes located on the sex chromosomes
Alleles are carried on the X chromosome,
not the Y chromosome
![Page 9: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/9.jpg)
Polygenic inheritance A trait that is controlled by
more than one gene Genes may be on different
chromosomes Each gene may have more
than one allele Trait usually expressed in a
continuous range of variability
![Page 10: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/10.jpg)
Environmental factors
External Gene may not be expressed due to
temperature, nutrition, light, chemicals, infection
For example, this bacteria
is different color when
grown at different temperature
![Page 11: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/11.jpg)
Environmental factors
InternalMales and females differ due to hormonesAge may change trait expression
![Page 12: 12.2 Complex patterns of inheritance. Complex patterns of inheritance Mendel’s experiments show simple inheritance with recessive and dominant alleles](https://reader031.vdocuments.net/reader031/viewer/2022032015/56649ced5503460f949bac05/html5/thumbnails/12.jpg)
Complex patterns of inheritance
Mendel’s idea that heredity is a composite of many traits still holds
Later researchers have filled in details