BIOL1003 Lecture Notes - Lecture 15: Phenotype, Allele, Mendelian Inheritance

41 views19 pages
Define the relationship of genotype and phenotype
Genotype determines phenotype
-
e.g. Tt, TT, tt
Genotype - genetic makeup of an organism, specific allelic composition
-
Phenotype - set of detectable characteristics or traits of an organism, appearance
-
e.g. AA or Aa = normal pigmentation, aa = albinism phenotype
15a)
4:04 PM
15. Inheritance Page 1
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 19 pages and 3 million more documents.

Already have an account? Log in
Define alleles, heterozygosity and homozygosity
Each chromosome contains genes
-
Each gene codes for characteristic, determines proteins in a cell
-
Genes - discrete hereditary factors that determine traits
-
Locus - position of gene on a chromosome
-
Allele
Different forms of a gene on homologous chromosomes
-
e.g. Aa, aa, AA
-
Dominant allele - produces normal enzymes, appears in phenotype
-
Recessive - produces abnormal enzyme, does not appear in phenotype
-
Heterozygous
2 alleles are slightly different for one trait
-
e.g. Aa
-
Homozygous
2 alleles are identical for one trait
-
e.g. aa
-
Genome
All genes in one homologous set of 23 chromosomes in one individual
-
15b)
11:07 PM
15. Inheritance Page 2
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 19 pages and 3 million more documents.

Already have an account? Log in
Describe meiosis and the consequences of recombination
During meiosis, chromosomes distributed so each gamete receives only one chromosome
from each homologous pair
-
Recombination
Pair of sex chromosomes separates so each secondary oocyte receives one X chromosomes,
whereas each sperm cell receives either an X or Y chromosome
-
Genes on a given chromosome linked, so tend to be inherited as a set rather than as
individual genes because chromosomes segregate during meiosis
Homologous chromosomes may exchange genetic info by CROSSING OVER in prophase
Resulting zygote has 47 or 46 chromosomes instead of 46
Segregation errors may occur, as homologous pair may not segregate e.g. one daughter
cell receives both chromosomes, while the other receives none
Random distribution of genes
-
15c)*
Monday, 5 June 2017
1:15 PM
15. Inheritance Page 3
Unlock document

This preview shows pages 1-3 of the document.
Unlock all 19 pages and 3 million more documents.

Already have an account? Log in

Document Summary

Genotype - genetic makeup of an organism, specific allelic composition e. g. tt, tt, tt. Phenotype - set of detectable characteristics or traits of an organism, appearance e. g. aa or aa = normal pigmentation, aa = albinism phenotype: inheritance page 1. Each gene codes for characteristic, determines proteins in a cell. Genes - discrete hereditary factors that determine traits. Locus - position of gene on a chromosome. All genes in one homologous set of 23 chromosomes in one individual: inheritance page 2. During meiosis, chromosomes distributed so each gamete receives only one chromosome from each homologous pair. Pair of sex chromosomes separates so each secondary oocyte receives one x chromosomes, whereas each sperm cell receives either an x or y chromosome. Genes on a given chromosome linked, so tend to be inherited as a set rather than as individual genes because chromosomes segregate during meiosis. Homologous chromosomes may exchange genetic info by crossing over in prophase.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

Related Questions