Northern Thai/Lanna and many Lao are genetically much closer to Viets than to other Thais

Laos and Hmong are between East Asians & South East Asians. 

@dyno

Of course. They are still Southeast Asians. Not implying they are East Asian just because they are closer to Viets than to other Thais. And many SE Asians can still have monolids and look East Asian without having Chinese if they are pure Mongoloids and lack Hoabinhian/Negrito, Indian, Papuan, Euro or any other non-Mong ancestries including many isolated Austronesian tribes.

Genetically they are much closer to the rest of SEA than to most East Asians/NE Asians.

Also Vietnamese are genetically SE Asian anyway being mostly Tai Kradai (despite speaking an Austroasiatic tongue) with varying degrees of Han Chinese and some Austroasiatic admixtures. And are closest to Dai of Yunnan and Guangxi Han (who are literally Sinicized natives with some Han admixture)

Most other Thais especially Central, Eastern and Southern regions are a mish mash/clusterfuck of mostly assimilated Mon, Khmer, Malay with varying degrees of Chinese, Indian, Negrito, European and West Asian (mainly Iranian) lineages.

Posted by: @qamzardaan

@naval 

Actually its the opposite. Thais are more mixed than Viets. Viet DNA results I have seen are fairly homogenous while Thai ones varied from being totally ethnic Chinese, to being mostly Khmer or Malay/Indonesian genetically, having high Indian/South Asian blood, to being a weird Chinese+ Khmer or Malay/Indo +some Indian or Euro mix, to being genetically mostly Lao/Tai. 

Only 4 major groups in Thailand compared to 7 in Vietnam 

List of ethnic groups in Vietnam - Wikipedia

Thailand has 71 ethnic groups. 

to me even Vietnamese from the north look SEA. Not common to see EA look. 

look at the pictures of these Vietnamese migrants found in a truck in England. They look SEA to me, except with light skin. Light skin is not uncommon in Vietnam.

https://www.dailymail.co.uk/news/article-8822977/Vietnamese-migrants-dead-Essex-lorry-killed-greedy-people-smugglers-court-hears.html

Pictures of the Essex lori victims and where they were from.