a bonobo humanity?

get it got it good

What’s a haplotype? It’s a bunch of alleles, so I have to be clear first about alleles. A haplotype, also known as a haploid genotype, is a set of alleles inherited (as a set) from a single parent.

Alleles are pretty complex, at least to me. I think of Mendel and his peas, but it’s vague. Looking up a definition hasn’t helped much. It might, or might not, be better to start with DNA and/or RNA, and of course I know something about these macromolecules and their structure. They’re made up of nucleotides, and an allele is described as ‘a variant of the sequence of nucleotides at a particular location, or locus, on a DNA molecule’. This doesn’t help much. Do I repeat myself?

I’ll keep trying. There are haploid cells and diploid cells. In humans they’re called gametes – the sperm and the eggs, and they each have 23 chromosomes. Fertilisation of eggs by sperm creates zygotes which are paired – 23 chromosomes from each gamete type. Twenty-three pairs of haplotype make a genotype.

Why am I bothering with this? I can’t remember now, but I think it was about alleles. There is a problem in my mind about a haplotype, say inherited from Mum, and this ‘bunch of alleles’ thing. I mean, what’s the difference between an allele and a gene?  

So I plug this into the machine. It seems that genes are things that code for things. In the phenotype. Your phenotype is the expression of your genes. Hair colour, penis size, intelligence maybe. Also I suppose your species. Bonobos have 24 pairs, but so do chimps. So…

Whales, since I’ve been focussing on them a bit lately, have mostly 44 chromosomes (22 pairs), but some species have 42. 

Anyway this all began with talk on social media about XY and XX chromosomes, male and female humans and longevity. XY is male (for humans and some other mammals, and some fish, snakes and even plants). These are the ‘sex chromosomes’, at least in these species. That’s to say, the sex-determining chromosomes. 

So a karyotype is, for my information, ‘the general appearance of the complete set of chromosomes in the cells of a species or in an individual, mainly including their sizes, numbers and shapes’. The sex chromosomes, obviously, are part of that karyotype, and they’re not always named XY or XX. Bird sex chromosomes, very interestingly, are ZW for females and ZZ for males. And what researchers are finding, in this doubling up (ZZ for male birds, XX for female humans) has some effect on their longevity – male birds, on average, and somewhat dependent on species – live longer than females, while female humans, and other mammals with XX chromosomes, live longer, on average, than males. Correlation or causation? 

But all of this stuff on haplotypes, and full genotypes, is intrinsically interesting, and I could do a complete free online course on it, maybe…?

So if you know the genotypes of both your parents, could you work out their particular contribution to your phenotype? ‘I got my braininess from mum and my good looks from dad’ type thing? I should listen to the Sapolsky videos online maybe…?

If only I was 40 years younger. Still my genotype, and some luck, has kept me alive thus far…