PSYCH 212 Lecture Notes - Lecture 3: Bad Copy, Quantitative Trait Locus, Y Chromosome
Psych 212 –Chapter 3
Fertilization also referred to as conception, is the process by which sperm and ovum (male
and female gametes, or sex cells –combine to create a single cell, zygote; which eventually ends
up producing a baby.
1. Alleles genes that produce alternative expressions of a characteristic (such as
presence or absence of dimples) alleles are alternative versions of the same gene. Every
person receives one maternal and one paternal allele for a given trait.
2. Homozygous when both alleles are the same the person is homozygous characteristic
3. Heterozygous when both alleles are different the person is heterozygous for the
characteristic
4. Polygenic inheritance pattern of inheritance where multiple genes at different sites
on a chromosome affect a complex trait (like intelligence)
5. Mutations permanent alterations in genes or chromosomes that usually produce
harmful characteristics but provide the raw material of evolution
6. Multifactorial Transmission combination of genetic and environmental factors to
produce certain complex traits (personality, intelligence, or musical ability)
7. Sex-linked inheritance in humans the Y chromosome is smaller and carries far fewer
genes than the X chromosome. One outcome of this is that the males receive only one
copy of any gene that happens to be carried on the sex chromosomes, whereas a female
carries 2 copies. So, if the girl gets a ad opy, sie she has 2 she ill hae a backup
copy. Whereas the male has a bad copy and will express it. If a female does inherit sex-
liked oditios, it’s likely that her father ad other ere arriers of the ad gee.
Dominant vs. Recessive Traits
Dominant genes override recessive genes so in order to get a recessive trait (such as blue eyes),
you must acquire two recessive genes)
Expected Genotypic Frequencies
o With 4 children, there is a 25% chance that each will be able to curl their
tongue.
Expected Phenotypic Frequencies
o Tongue curling = 75%
o No tongue curling =25%
Gene Expression:
Genotype
o Actual genetic makeup or allele combination
o Ex. Tongue curling ability: DD or Dd (could have either one)
Phenotype
o Observable expression of genetic make-up
o Product of genotype
o DD or Dd =tongue curling
Genotype batter, sugar, flour, eggs, milk
Phenotype cake, muffins, etc.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
One outcome of this is that the males receive only one copy of any gene that happens to be carried on the sex chromosomes, whereas a female carries 2 copies. So, if the girl gets a (cid:271)ad (cid:272)opy, si(cid:374)(cid:272)e she has (cid:862)2(cid:863) she (cid:449)ill ha(cid:448)e a backup copy. Whereas the male has a bad copy and will express it. If a female does inherit sex- li(cid:374)ked (cid:272)o(cid:374)ditio(cid:374)s, it"s likely that her father a(cid:374)d (cid:373)other (cid:449)ere (cid:272)arriers of the (cid:862)(cid:271)ad(cid:863) ge(cid:374)e. Dominant genes override recessive genes so in order to get a recessive trait (such as blue eyes), you must acquire two recessive genes) Expected genotypic frequencies: with 4 children, there is a 25% chance that each will be able to curl their. Expected phenotypic frequencies tongue: tongue curling = 75, no tongue curling =25% Genotype: actual genetic makeup or allele combination, ex. Tongue curling ability: dd or dd (could have either one)
