3: Genes, alleles and traits Flashcards
What is a genome
Entire set of DNA instructions found in a cell
Humans = 23 pairs of chromosomes
What is a chromosome
Threadlike structure made of protein and a single molecule of DNA, carry the genomic information from cell to cell
How many chromosomes do humans have
22 pairs of autosomes and one pair of sex chromosomes
Protein in transcription
RNA polymerase
What is a gene
Basic unit of inheritance
Role of genes
Contain info needed to specify physical and biological traits
Code for proteins, segments of proteins
DNA undergoes… RNA undergoes…
Transcription into RNA
Translation into proteins
Why are chromosomes relevant to animal breeding
Differences in chromosomes = difference in gene activity = difference in phenotype
Passed to progeny
What is segragation
Separation of paired alleles during germ cell formation
What is independent assortment
Independent segregation of alleles at different loci
How does a 2-bp deletion in the canine MSTN coding sequence affect whippets
Normal (M) allele has two bases that are missing in the abnormal (m) allele
m allele = early stop codon leads to a shorter MSTN protein = bully whippet
What do you risk when mating two M/m whippets
Gametes carry either M or m allele in equal number
Three possible genotypes:
0.25 MM
0.5 Mm
0.25 mm
What is an allele
One of two or more versions of DNA sequence at a given genomic location
What is a genotype
A scoring of the type of variant present at a given location in the genome
e.g. MM, Mm, mm
What is a locus
A physical site or location within a genome
